InfoMagic Standards 1994 January/InfoMagic Standards - January 1994.iso/ccitt/1988/troff/3_5_04.tro

Text File | 1991-12-12 | 95KB | 4,080 lines

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.nr LL 40.5P
.nr ll 40.5P
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.rs
\v | 5i'
.LP
\fBMONTAGE:\ \fR REC.\ G.956 EN T\* | TE DE CETTE PAGE
.IP
\v'15P'
\fB9.6\ Digital section and digital transmission systems for ISDN
customer access\fR
.sp 1P
.RT
.sp 2P
.LP
\fBRecommendation\ G.960\fR
.RT
.sp 2P
.sp 1P
.ce 1000
\fBDIGITAL\ SECTION\ FOR\ ISDN\ BASIC\ RATE\ ACCESS\fR
.EF '%    Fascicle\ III.5\ \(em\ Rec.\ G.960''
.OF '''Fascicle\ III.5\ \(em\ Rec.\ G.960    %'
.ce 0
.sp 1P
.ce 1000
\fR \fI(Melbourne, 1988)\fR
.sp 9p
.RT
.ce 0
.sp 1P
.LP
\fB1\fR     \fBGeneral\fR
.sp 1P
.RT
.sp 1P
.LP
1.1
    \fIScope\fR
.sp 9p
.RT
.PP
This Recommendation describes the characteristics of a digital
section for the ISDN basic rate access between the user network interface
(at T\ reference point, defined in Recommendation\ I.411) and the local
exchange (at V\d1\u\ reference point defined in Recommendation\ Q.512)
supporting the
recommended channel structure 2B\ +\ D and the required additional functions.
.PP
In this Recommendation and unless otherwise indicated, the term TE is used
to indicate terminating layer\ 1 aspects of\ TE1, TA and\ NT2 functional
groups.
.PP
When the term TE indicates terminating layer 1 aspects of TE1,
then according to Figure\ 2/I.411, the S\ and T\ reference points coincide.
.PP
The terminology used in this Recommendation is very specific and
not contained in the relevant terminology Recommendations. Therefore Annex\ B
to this Recommendation provides terms and definitions used in this
Recommendation.
.RT
.sp 1P
.LP
1.2
    \fIConfiguration\fR
.sp 9p
.RT
.PP
Figure 1/G.960 shows the boundaries of the digital section in
relation to the digital system definition.
.RT
.PP
The concept of the digital section is used in order to allow a
functional and procedural description and a definition of the network
requirements.
.PP
Note that reference point T and V\d1\uare not identical and therefore the
digital section is not symmetric.
.PP
The concept of a digital transmission system is used in order to
describe the characteristics of a implementation, using a specific medium,
in support of the digital section.
.PP
\fINote\fR \ \(em\ The T and V reference points are defined in
Recommendations\ I.411 and\ Q.512.
.bp
.RT
.LP
.rs
.sp 19P
.ad r
\fBFigure 1/G.960, p.1\fR
.sp 1P
.RT
.ad b
.RT
.sp 1P
.LP
1.3
    \fIApplication\fR
.sp 9p
.RT
.PP
The basic access digital section may be applied as given in
Figure\ 2/G.960 for:
.RT
.LP
    \(em
    direct access to the local exchange (V\d1\u\(hyreference point);
.LP
    \(em
    access via a basic access multiplex equipment
(V\d4\u\(hyinterface) to the local exchange;
.LP
    \(em
     access via a basic access concentrator (V\d2\u\(hyinterface) to the local
exchange;
.sp 1P
.LP
1.4
    \fIAbbreviations\fR
.sp 9p
.RT
.PP
A number of abbreviations are used in this Recommendation. Some of them
are commonly used in the ISDN reference configuration while others are
created only for this Recommendation. The last one are given in the
following:
.RT
.LP
    C\dV\\d1\u    Control Channel at V\d1\ureference point
.LP
    DS
    Digital Section
.LP
    FE
    Function Element used between ET and LT
.LP
    FII
    Failure Indication Information
.LP
    INFO
    Information element defined at the user network
interface
.LP
    SIG
    Signal between LT an NT1
.sp 2P
.LP
\fB2\fR     \fBModelling and relationship between the digital section\fR
\fBand the ET\fR
.sp 1P
.RT
.PP
The general model shown in Figure 3/G.960 depicts the whole ISDN
customer access layer 1 and adjacent entities and provides the basis to
describe the functions performed by the digital section and those performed
by TE, ET and system management and how various functions are grouped.
In
particular, according to this model the activation/deactivation procedures
and maintenance functions specified in this Recommendation are not confined
to
functions performed by the digital section but include functions associated
with\ ET layer\ 1.
.bp
.RT
.LP
\fR .rs
.sp 36P
.ad r
\fBFigure 2/G.960 p.2\fR
.sp 1P
.RT
.ad b
.RT
.PP
This model includes primitive procedures between ET layer 1,
ET\ layer\ 2 and system management:
.RT
.LP
    i)
    I.430 to I.440/I.441 interactions between ET layer 1 and ET
layer 2, and ET layer\ 1 and system management based on\ PH and\ MPH
primitives, respectively, as defined in Recommendation\ I.430. These
interactions are for the support of functions specified in
Recommendations\ I.440 and\ I.441;
.LP
    ii)
    interactions between ET layer 1 and system management for
the support of functions associated with the digital section, based on
MPH primitives.
.PP
The primitive procedures within TE comply with the specification according
to Recommendation\ I.430.
.PP
This model does not constrain layer 1 arrangements between LT and
NT1, (it is also applicable to remote access as shown in Figure\ 2/G.960), or
the digital transmission system technology.
.bp
.RT
.LP
.rs
.sp 28P
.ad r
\fBFigure 3/G.960, p.\fR
.sp 1P
.RT
.ad b
.RT
.sp 2P
.LP
\fB3\fR     \fBFunctions\fR
.sp 1P
.RT
.PP
Figure 4/G.960 shows the functions which have to be supported by
the basic access digital section.
.RT
.sp 1P
.LP
3.1
    \fIB channel\fR
.sp 9p
.RT
.PP
This function provides, for each direction of transmission, two
independent 64\ kbit/s channels for use as B\ Channels (as defined in
Recommendation\ I.412).
.RT
.sp 1P
.LP
3.2
    \fID channel\fR
.sp 9p
.RT
.PP
This function provides, for each direction of transmission, one
D\ Channel at a bit rate of 16 kbit/s (as defined in
Recommendation\ I.412).
.RT
.sp 1P
.LP
3.3
    \fIBit timing\fR
.sp 9p
.RT
.PP
This function provides bit (signal element) timing to enable the
receiving equipment to recover information from the aggregate bit stream.
Regarding the V\d1\ureference point, the bit timing function is used for
both transmit and receive data.
.RT
.sp 1P
.LP
3.4
    \fIOctet timing\fR
.sp 9p
.RT
.PP
This function provides 8 kHz octet timing for the B Channels.
.bp
.RT
.LP
.rs
.sp 28P
.ad r
\fBFigure 4/G.960, p.4\fR
.sp 1P
.RT
.ad b
.RT
.sp 2P
.LP
3.5
    \fIActivation\fR
.sp 1P
.RT
.sp 1P
.LP
3.5.1
    \fIActivation from ET\fR
.sp 9p
.RT
.PP
This function places all the functions of the digital section into a normal
operating mode and supports the activation of the interface at the T reference
point according to Recommendation\ I.430. This takes into
account:
.RT
.LP
    \(em
    power down mode;
.LP
    \(em
    initial power up;
.LP
    \(em
    a failure condition.
.PP
The procedures and exchange of information are described in \(sc 5 of this
Recommendation.
.PP
An activation should be possible to a state which allows
maintenance actions to be performed in the digital section even when there
is no customer equipment connected to the T\ reference point.
.PP
In the case of a basic access digital section making use of a digital transmission
system for a metallic line one additional mode of operation may be applied
for activation/deactivation, which is to activate/deactivate the
digital section only. This is optional.
.RT
.sp 1P
.LP
3.5.2
    \fIRequest for activation from TE\fR
.sp 9p
.RT
.PP
This function supports activation of the digital section and of the interface
at the T\ reference point according to Recommendation\ I.430.
.PP
These functions are conveyed by the C\dV\\d1\uchannel (see \(sc\ 7).
.bp
.RT
.sp 1P
.LP
3.6
    \fIDeactivation\fR
.sp 9p
.RT
.PP
This function is specified in order to permit the interface at the T\ reference
point and the digital section to be placed in a low power
consumption mode. The procedures and exchange of information are described
in \(sc\ 5 of this Recommendation.
.PP
Deactivation should be initiated only by the exchange (ET).
.PP
This function is conveyed by the C\dV\\d1\uchannel (see \(sc 7).
.RT
.sp 1P
.LP
3.7
    \fIPower feeding\fR
.sp 9p
.RT
.PP
This function provides for remote power feeding of NT1 and
optionally the TE via the user network interface in accordance with
Recommendation\ I.430, \(sc\ 9.
.RT
.sp 1P
.LP
3.8
    \fIOperation and maintenance\fR
.sp 9p
.RT
.PP
This function supports required actions and information for
operating and maintaining the digital section controlled by the ET as defined
in Recommendation\ I.603.
.PP
Four categories of functions have been identified:
.RT
.LP
    \(em
    commands regarding LT, regenerator, or NT1;
.LP
    \(em
    information from LT, regenerator, or NT1;
.LP
    \(em
    indications of fault conditions;
.LP
    \(em
    control of digital section power feeding.
.PP
These functions are conveyed by the C\dV\\d1\uchannel (see \(sc 7).
.sp 2P
.LP
\fB4\fR     \fBNetwork performance\fR
.sp 1P
.RT
.sp 1P
.LP
4.1
    \fIAvailability\fR
.sp 9p
.RT
.PP
The definition of availability is given in Annex A of
Recommendation\ G.821. The availability objective of the digital section
should be consistent with the availability requirement for the hypothetical
reference digital section as given in Recommendations\ G.801 and\ I.350.
.RT
.sp 1P
.LP
4.2
    \fISignal transfer delay\fR
.sp 9p
.RT
.PP
Signal transfer delay is specified for B Channels and is defined as absolute
signal delay between\ T and\ V\d1\ureference points for each direction
of transmission. The value is for further study. The relevant Recommendations
have to be taken into account (e.g.\ signal transmission delay when the
signal represents speech must be taken into account as one component of
the end\(hyto\(hyend delay requirement of Recommendation\ G.114).
.RT
.sp 1P
.LP
4.3
    \fIError performance\fR
.sp 9p
.RT
.PP
Error performance must be consistent with the requirements given in Recommendation\
G.821.
.RT
.sp 2P
.LP
4.4
    \fIJitter\fR
.sp 1P
.RT
.sp 1P
.LP
4.4.1
    \fIOutput/input jitter at T reference point\fR
.sp 9p
.RT
.PP
The requirements are defined in \(sc 8 of Recommendation I.430.
.RT
.sp 1P
.LP
4.4.2
    \fIJitter at V\fI
.sp 9p
.RT
.EF '%    \fI1\ reference\ point''
.OF '''\fI1\ reference\ point    %'
.PP
The input jitter limits are for further study.
.RT
.sp 2P
.LP
\fB5\fR     \fIActivation/deactivation\fR
.sp 1P
.RT
.sp 1P
.LP
5.1
    \fIFunctional capabilities\fR
.sp 9p
.RT
.PP
The digital section provides the layer 1 signalling capability and the
necessary procedures to enable:
.RT
.sp 1P
.LP
5.1.1
    \fICustomer equipment at the user side of reference point T\fR
.sp 9p
.RT
.LP
    to activate the layer 1 of the user\(hynetwork interface at reference
point\ T and, if not already activated, the digital section.
.bp
.sp 1P
.LP
5.1.2
    \fIEquipment at the network side of V\fI
.sp 9p
.RT
.EF '%    \fI1\ reference\ point\ to''
.OF '''\fI1\ reference\ point\ to    %'
.LP
    a)
    activate:
.LP
    1)
    the layer 1 of the user\(hynetwork interface at reference
point\ T and, if not already activated, the digital section (this
activation is related to call control), or
.LP
    2)
    the digital section only (this activation is related to
controlling the configuration of the access; it is a network
opinion),
.LP
    b)
    deactivate:
.LP
    1)
    the layer 1 of the user\(hynetwork interface at reference
point\ T and the digital section, or
.LP
    2)
    the layer 1 of the user\(hynetwork interface at reference
point\ T only.
.PP
The functional capabilities defined in \(sc 5.1.2 | ) | ) allow
maintenance actions in the digital section which do not impact the deactivated
user\(hynetwork interface at reference point\ T to be performed and make
provision for the implementation of a non\(hytransparent loopback\ 2. If
required in some applications, they also permit the digital section to
be placed in a
mode where the full information transfer capability is available while the
user\(hynetwork interface at reference point\ T remains deactivated.
.PP
The procedures for the activation or deactivation of the layer 1 of
the user\(hynetwork interface at reference point\ T comply with the
Recommendation\ I.430, \(sc\ 6.2. These procedures are based on a repertoire
of INFO signals as defined in Recommendation\ I.430 (Table\ 2/I.430).
.PP
The procedures at V\d1\ureference point are based on a repertoire of function
elements (FEs). These FEs have specific relationships to primitives
between the ET layer\ 1 and ET layer\ 2, and ET layer\ 1 and system management
for the activation or deactivation of the layer\ 1 of the user\(hynetwork
interface in accordance with Recommendation\ I.430, \(sc\ 6.2 and Recommendation\
I.440 and\ I.441. The means for defining these interactions are the primitive
procedures (see
Figure\ 5/1.430) based on a repertoire of PH\(hy and MPH\(hyprimitives.
.RT
.sp 2P
.LP
5.2
    \fIModelling\fR
.sp 1P
.RT
.sp 1P
.LP
5.2.1
    \fIGeneral\fR
.sp 9p
.RT
.PP
The model for activation/deactivation procedures is given in \(sc\ 2.
.PP
It is recognized that activation/deactivation is a process between
customer equipment and local exchange requiring appropriate functionality at
both ends. The model contained in \(sc\ 2 includes the functional blocks
relevant to activation/deactivation and depicts the primitives related
to the
activation/deactivation procedures.
.RT
.sp 1P
.LP
5.2.2
    \fIPartitioning of functions\fR
.sp 9p
.RT
.PP
Recommendation I.430 defines the network side of the user\(hynetwork interface
at reference point\ T as one functional block which supports the
layer\ 1 activation/deactivation procedures across the T\ reference point
and the primitive procedures at the ET layer\ 1/ET layer\ 2 boundary and
ET
layer\ 1/system management boundary. This block includes the functional
groupings NT1, LT and ET layer\ 1.
.PP
This concept is described in terms of a state machine, called the G
state machine in Recommendation\ I.430.
.PP
In order to describe the relationship between signals across the
user\(hynetwork interface at reference point\ T and function elements across
reference point\ V\d1\u, and the relationship between function elements across
reference point\ V\d1\uand primitives, two state machines are defined. One in
the digital section (DS virtual state machine), and one at the network
side of the V\d1\ureference point (ET layer\ 1 virtual state machine).
Figure\ 5/G.960
illustrates this approach.
.PP
In addition to primitives defined in Recommendation I.430 and I.441
related to call control, Figure\ 5/G.960 also introduces a new set of primitives
related to configuration control and the control of loopbacks. Partitioning
of activation/deactivation procedures between two state machines is used
for the convenience of easy and accurate description. The ET layer\ 1 state
machine is to be viewed as virtual, not intended to imply any particular
implementation.
.RT
.PP
However, in order to implement a customer access the virtual DS
state machine has to be partitioned further. Figure 6/G.960 shows the partition
of the DS state machine into NT1 state machine (NT\(hystates) and LT state
machine (LT\(hystates).
.PP
The NT1 state machine supports user\(hynetwork interface procedures in
accordance with Recommendation\ I.430 based on the INFOs, and interacts
with the LT state machine by means of a signal repertoire (SIGs) which
has to be
supported by the line transmission system. The LT state machine interacts
with the ET layer\ 1 state machine by means of a set of function elements
(FEs). The ET layer\ 1 state machine contains those states which represent
the local
exchange view of the status of the interface at reference point\ T and the
digital section. It supports the already specified primitive procedures to
provide services to ET layer\ 2 and system management in accordance with
Recommendation\ I.430, and additional primitive procedures for the support of
functions associated with the digital section.
.bp
.RT
.LP
.rs
.sp 23P
.ad r
\fBFigure 5/G.960, p.5\fR
.sp 1P
.RT
.ad b
.RT
.PP
Figure 6/G.960 provides information for the description of the
transmission system which is given in Recommendation\ G.961.
.LP
.rs
.sp 23P
.ad r
\fBFigure 6/G.960, p.\fR
.sp 1P
.RT
.ad b
.RT
.LP
.bp
.sp 1P
.LP
5.2.3
    \fILocation of timers T1 and T2\fR
.sp 9p
.RT
.PP
In the following description of the DS and ET layer 1 state
machines, timer T1 will be associated with ET layer\ 1 (ET layer\ 1 state
machine) while timer T2 will be associated with the digital section (DS
state machine).
.PP
The association of timer T1 with layer 1 of the ET is applied for the convenience
of easy description but may be implemented anywhere while being
functional part of the ET. The exact location of timer T2 within the digital
section does not impact the description of the DS state machine.
.RT
.sp 1P
.LP
5.3
    \fIActivation/deactivation procedures\fR
.sp 9p
.RT
.PP
The procedures allow the activation/deactivation of the
user\(hynetwork interface at reference point\ T. The activation may be
invoked by either side while deactivation may only be invoked by the network.
The overall activation/deactivation procedures can be divided into three
classes:
.RT
.LP
    a)
    basic procedures for call control used to activate the
layer\ 1 of the user\(hynetwork interface at the T\ reference point and if
not already activated, the digital section;
.LP
    b)
    procedures to control loopbacks;
.LP
    c)
    procedures to control the configuration.
.sp 2P
.LP
5.3.1
    \fIBasic characteristics of the procedures\fR
.sp 1P
.RT
.sp 1P
.LP
5.3.1.1
    \fIPriority\fR
.sp 9p
.RT
.PP
Priority refers to contention resolution between
activation/deactivation requests which have been invoked concurrently.
.PP
If contention between conflicting activation/deactivation requests
from layer\ 2 and system management occurs it is resolved in the ET layer\ 1
state machine, which will then pass to the V\d1\ureference point a coordinated
set of Function Elements (FEs). Table\ 1/G.960 shows the ET layer\ 1 state
machine priority order.
.RT
.ce
\fBH.T. [T1.960]\fR
.ce
TABLE\ 1/G.960
.ce
\fBPriority order of request in the ET layer 1 state machine\fR
.ps 9
.vs 11
.nr VS 11
.nr PS 9
.TS
center box;
cw(180p) | cw(48p) .
Type of request    Priority order
_
.T&
lw(180p) | lw(48p) .
Deactivation request    3 (highest)
.T&
lw(180p) | lw(48p) .
Loopback    2
.T&
lw(180p) | lw(48p) .
 {
Call control activation request
 }    1
.T&
lw(180p) | lw(48p) .
 {
Digital section only activation/deactivation request from the ET
side
 }    0 (lowest)
_
.TE
.nr PS 9
.RT
.ad r
\fBTable 1/G.960 [T1.960], p.\fR
.sp 1P
.RT
.ad b
.RT
.PP
If contention between conflicting activation/deactivation requests from
ET side and user side occurs it is resolved in the DS state machine.
Table\ 2/G.960 shows the DS state machine priority order.
.ce
\fBH.T. [T2.960]\fR
.ce
TABLE\ 2/G.960
.ce
\fBPriority order of requests in the DS state machine\fR
.ps 9
.vs 11
.nr VS 11
.nr PS 9
.TS
center box;
cw(180p) | cw(48p) .
Type of request    Priority order
_
.T&
lw(180p) | lw(48p) .
 {
Request from ET side except digital section only activation
 }    2 (highest)
.T&
lw(180p) | lw(48p) .
 {
Call control activation request from user side
 }    1
.T&
lw(180p) | lw(48p) .
 {
Digital section only activation/deactivation request from the ET side
 }    0 (lowest)
_
.TE
.nr PS 9
.RT
.ad r
\fBTable 2/G.960 [T2.960], p.\fR
.sp 1P
.RT
.ad b
.RT
.LP
.bp
.sp 1P
.LP
5.3.1.2
    \fISystem management\fR
.sp 9p
.RT
.PP
Some assumptions related to the system management are described in  Annex\ A.
.RT
.sp 1P
.LP
5.3.1.3
    \fILoopbacks\fR
.sp 9p
.RT
.PP
In case a transparent loopback 2 is applied, the NT1 shall send
INFO\ 4 frames toward the user with the D\(hyecho\(hychannel set to binary
ZERO.
.PP
With a transparent loopback 1, the NT1 (when able to activate the
user\(hynetwork interface at the T reference point) shall send INFO\ 4 frames
toward the user with the D\(hyecho\(hychannel set to binary ZERO or operating
normally.
.RT
.sp 1P
.LP
5.3.1.4
    \fIProtection of layer 2 frames\fR
.sp 9p
.RT
.PP
According to Recommendation I.430 \(sc 6.2.6.1 a TE is allowed to take
up to 100\ ms to synchronize on INFO\ 2, no lower time limit is defined.
The
different time each TE may take to synchronize on INFO\ 2 affects the offering
of an incoming call in layer\ 1 multiple terminal arrangements. The fastest
TE notifies to the network that the access is activated and the message
offering the incoming call (SETUP) may be transmitted (TE ready to receive
the message) while other TEs are not yet ready to receive the message.
.PP
This could result in the slow TEs loosing all or part of the incoming messages
(layer\ 2 frames).
.PP
The protection mechanism is for further study.
.RT
.sp 1P
.LP
5.3.1.5
    \fIStructure of the tables\fR
.sp 9p
.RT
.PP
Both the DS state transition table and the ET layer 1 state
transition table are structured such that the three classes of the
activation/deactivation procedures described at the beginning of \(sc\ 5.3 are
clearly separated. This allows implementation of the basic procedure
only.
.RT
.sp 1P
.LP
5.3.1.6
    \fITransmission of INFO 2\fR
.sp 9p
.RT
.PP
In the following procedures two different internal events of the
digital section are considered to start transmission of INFO\ 2:
.RT
.LP
    a)
    the transmission system is synchronized in the direction LT  to NT1
.LP
    b)
     the transmission system is synchronized in both directions of transmission
(see Note\ 2, Table\ 3/G.960)
.sp 2P
.LP
5.4
    \fIDescription of the state transtition tables\fR
.sp 1P
.RT
.sp 1P
.LP
5.4.1
    \fIDescription of the DS state transition table\fR
.sp 9p
.RT
.sp 1P
.LP
5.4.1.1
    \fIDigital section states (DS\(hystates)\fR
.sp 9p
.RT
.PP
Hereafter are defined the states that the digital section may enter as
a result of: INFOs received across reference point\ T, function elements
(FEs) received across reference point\ V\d1\u, or internal events.
.PP
The DS\(hystates are classified according to the functionality they
support as follows:
.RT
.LP
    i)
     DS 1.X states for the support of functionality according to Recomendation\
I.430;
.LP
    ii)
     DS 2.X states for the support of functionality related to loopbacks (these
states complement DS\ 1.X states);
.LP
    iii)
     DS 3.X states for the support of functionality related to digital section
only activation/deactivation (these states complement DS 1.X
states).
.PP
The X represents the specific state within each mode. Some values of X
are not used in mode\ 2 and\ 3 in order to have a consistent use of them.
.bp
.sp 1P
.LP
5.4.1.1.1\ \ State DS 1.0  (fully deactivated): in this state state, the
digital section is in a non\(hyoperational mode and as seen from the user
side of reference point\ T, the network side is in state G1 according to
Recommendation\ I.430 \(sc\ 6.2.1.2.1.
.sp 9p
.RT
.LP
5.4.1.1.2\ \ State DS 1.1 (pending activation access): this transitional
state is entered when an activation of the access was requested by the
network (by means of
either the PH\(hy or MPH\(hyACTIVATE\(hyREQUEST primitive) or the user
(by means of INFO 1\ across T\ reference point) while the digital section
was in the state DS\ 1.0. An awake process takes place to establish the
digital section conditions which allow the transmission of INFO\ 2 across
T\ reference point. As seen from the
user side of reference point\ T, the network side is in state G1 according to
Recommendation\ I.430 \(sc\ 6.2.1.2.1.
.LP
5.4.1.1.3\ \ State DS 1.2 (transitional state access activation): when
entering this transitional state the network initiates transmission of
INFO\ 2 across
reference point while waiting for the digital section to be fully synchronized
and the receipt of INFO\ 3. As seen from the user side of reference point\
T, the network side is in state G2 according to Recommendation\ I.430 \(sc\
6.2.1.2.2.
.LP
5.4.1.1.4\ \ State DS 1.3 (digital section fully activated): in this transitional
state, the digital section is synchronized in both directions of transmission
and the network sends INFO\ 2 across T\ reference point while waiting for
INFO\ 3. As seen from the user side of reference point\ T, the network
side is in
state\ G2 according to Recommendation\ I.430 \(sc\ 6.2.1.2.2. This state
is also
entered if loss of synchronization occurs at reference point\ T while in the
state DS\ 1.5.
.LP
5.4.1.1.5\ \ State DS 1.5 (interface at T activated): this is the normal
active stable state where the layer\ 1 service is available to the higher
layers. The network sends INFO\ 4 across\ T reference point and as seen
from the user side, the network side is in state\ G3 according to Recommendation\
I.430 \(sc\ 6.2.1.2.3.
.LP
5.4.1.1.6\ \ State DS 1.6 (pending deactivation access): this transitional
state is entered if the system management instructed the digital section
to
deactivate the access. As seen from the user side of reference point\ T, the
network side is in state G4 according to Recommendation\ I.430 \(sc\ 6.2.1.2.4.
.LP
5.4.1.1.7\ \ State DS 1.7 (transitional state access deactivation): in this
transitional state, the interface at reference point T is already deactivated.
The deactivation of the digital section is in progress. As seen from the
user side of reference point\ T, the network side is in state G1 according
to
Recommendation\ I.430 \(sc\ 6.2.1.2.1.
.LP
5.4.1.1.8\ \ State DS 1.8 (transitional state access deactivation): in this
transitional state, the digital section is already deactivated. The
deactivation of the interface at reference point\ T is in progress. As
seen from the user side of reference point\ T, the network side is in state\
G4 according to Recommendation\ I.430 \(sc\ 6.2.1.2.4.
.LP
5.4.1.1.9\ \ States DS 2.X: for further study.
.LP
5.4.1.1.10\ \ State DS 3.1 (pending activation digital section only): this
transitional state is entered when an activation of the digital section only
was
requested by the network (by means of the MPH\(hyDIGITAL SECTION ACTIVATE\(hyREQUEST
primitive, MHP\(hyDSAR). The digital section was previously in the state
DS\ 1.0 or a deactivation of the access was previously in progress. As
seen from the user side of reference point\ T, the network side is in state
G1 according to
Recommendation\ I.430 \(sc\ 6.2.1.2.1.
.LP
5.4.1.1.11\ \ State DS 3.2 (transitional state digital section activation):
this transitional state is entered when an activation of the digital section
only
was requested by the network (by means of the MPH\(hyDIGITAL SECTION
ACTIVATE\(hyREQUEST primitive, MPH\(hyDSAR). The deactivation of the access was
previously in progress. As seen from the user side of reference point\ T, the
network side is in state G4 according to Recommendation\ I.430 \(sc\ 6.2.1.2.4.
.LP
5.4.1.1.12\ \ State DS 3.3 (digital section only activated): in this stable
state, the digital section is synchronized in both directions of transmission
and this has been notified to the system management by means of the MPH\(hyDIGITAL
SECTION ACTIVATE\(hyINDICATION primitive (MPH\(hyDSAI). The network sends
INFO\ 0
across T\ reference point. As seen from the user side of reference point\
T, the network side is in state\ G1 according to Recommendation\ I.430
\(sc\ 6.2.1.2.1.
.LP
5.4.1.1.13\ \ State DS 3.4 (pending activation interface): this transitional
state is entered when an activation of the interface was requested by the
network (by means of either the PH\(hy or MPH\(hyACTIVATE\(hyREQUEST primitive)
or the user (by means of INFO\ 1 across the T\ reference point) while the
digital
section was already in the activated state, state DS\ 3.3. The network
immediately transmits INFO\ 2 across the T\ reference point. As seen from the
user side of reference point\ T, the network side is in state G2 according to
Recommendation\ I.430 \(sc\ 6.2.1.2.2.
.bp
.LP
5.4.1.1.14\ \ State DS 3.6 (pending deactivation interface): this transitional
state is entered if the system managemnt instructed the digital section to
deactivate the interface at reference point\ T but to remain activated.
As seen from the user side of reference point\ T, the network side is in
state\ G4
according to Recommendation\ I.430 \(sc\ 6.2.1.2.4.
.sp 1P
.LP
5.4.1.2
     \fIRepertoire of signals across the user\(hynetwork interface at the\fR
\fIT\ reference point\fR
.sp 9p
.RT
.PP
The definition of INFO signals is contained in Recommendation\ I.430 \(sc\
6.2.2.
.RT
.sp 1P
.LP
5.4.1.3
    \fIRepertoire of function elements at the V\fI
.sp 9p
.RT
.EF '%    \fI1\ reference\ point''
.OF '''\fI1\ reference\ point    %'
.PP
The function elements represent input signals which are consumed
if a state transition occurs, even if it is a null transition (remain in the
same state), and are not longer available to initiate one more state
transition.
.PP
The following repertoire of function elements associated with the
activation/deactivation procedures is defined:
.RT
.LP
    \(em
    FE\ 1\ \ (LT\ \(<-\ ET):
    activation request for the interface at
reference point\ T
.LP
    \(em
    FE\ 2\ \ (LT\ \(ra\ ET):
    request to start timer T1 within ET
layer\ 1
.LP
    \(em
    FE\ 3\ \ (LT\ \(ra\ ET):
    the digital section is activated
.LP
    \(em
    FE\ 4\ \ (LT\ \(ra\ ET):
    user\(hynetwork interface at the
T\ reference point is activated or loopback is operated
.LP
    \(em
    FE\ 5\ \ (LT\ \(<-\ ET):
    deactivation request for the digital
section and interface at reference point\ T
.LP
    \(em
    FE\ 6\ \ (LT\ \(ra\ ET):
    the digital section is deactivated and
the interface at reference point\ T will be or has been deactivated
.LP
    \(em
    FE\ 7\ \ (LT\ \(ra\ ET):
    error indication
.LP
    \(em
    FE\ 8\ \ (LT\ \(<-\ ET):
    activation request for loopback 2
.LP
    \(em
    FE\ 9\ \ (LT\ \(<-\ ET):
    activation request for loopback 1
.LP
    \(em
    FE\ 10\ (LT\ \(<-\ ET):
    activation request for loopback 1A
.LP
    \(em
    FE\ 11\ (LT\ \(<-\ ET):
    request to enter a state where the
digital section only is activated
.sp 2P
.LP
5.4.1.4
    \fISpecification of the procedures\fR
.sp 1P
.RT
.sp 1P
.LP
5.4.1.4.1\ \ \fIProcedures across the user\(hynetwork interface at reference\fR
\fIpoint\ T\fR
.sp 9p
.RT
.PP
The digital section supports the procedures across the
user\(hynetwork interface at reference point\ T in accordance with
Recommendation\ I.430 \(sc\ 6.2.
.RT
.sp 1P
.LP
5.4.1.4.2\ \ \fIDigital section state transition table\fR
.sp 9p
.RT
.PP
The state transition table, see Table\ 3/G.960, specifies the
procedures. It includes the actions to be taken on various events while in a
specific state (see \(sc\ 5.4.1.1 for the definition of the states). In
particular, the actions to support the activation/deactivation procedures
across the
reference point\ T in accordance with Recommendation\ I.430 (sequence of
INFOs in compliance with\ I.430). The procedures for loopback operation
require further study.
.RT
.LP
.rs
.sp 5P
.LP
.bp
.ce
\fBH.T. [1T3.960]\fR
.ps 9
.vs 11
.nr VS 11
.nr PS 9
.TS
center box;
cw(342p) .
TABLE\ 3/G.960
.T&
cw(342p) .
 {
\fBState transition table of digital section (DS state machine)\fR
 }
.TE
.TS
center box ;
cw(24p) | cw(24p) | cw(18p) | cw(24p) | cw(18p) | cw(24p) | cw(18p) | cw(24p) | cw(18p) | cw(48p) .
State number    DS 1.0  \fB(Note 2)\fR    DS 1.1  \fB(Note 2)\fR    DS 1.2  (Note 2)    DS 1.3  (Note 2)    DS 1.5  \fB(Note 2)\fR    DS 1.6  \fB(Note 2)\fR      DS 1.7  (Note 3)    DS 1.8  (Note 3)     {
DS\(hystates related to loopbacks
 }
.T&
cw(24p) | cw(24p) | cw(18p) | cw(24p) | cw(18p) | cw(24p) | cw(18p) | cw(24p) | cw(18p) .
INFO  SENT    INFO 0    INFO 0    INFO 2    INFO 2    INFO 4    INFO 0    INFO 0    INFO 0
_
.T&
cw(24p) | cw(24p) | cw(18p) | cw(24p) | cw(18p) | cw(24p) | cw(18p) | cw(24p) | cw(18p) .
FE 1    DS 1.1    na    na    na    na    DS 1.1    DS 1.1    DS 1.1
_
.T&
cw(24p) | cw(24p) | cw(18p) | cw(24p) | cw(18p) | cw(24p) | cw(18p) | cw(24p) | cw(18p) .
FE 5    na    Start\ T2 DS 1.6    Start\ T2 DS 1.6    Start\ T2 DS 1.6    Start\ T2 DS 1.6    na    na    na
_
.T&
lw(24p) | cw(24p) | cw(18p) | cw(24p) | cw(18p) | cw(24p) | cw(18p) | cw(24p) | cw(18p) .
Receiving  INFO 0  (Note\ 1)    \(em    \(em    \(em    \(em    FE 7 DS 1.3    \fBFE 7\fR DS 1.7    \(em    \fBFE 7\fR DS 1.0
_
.T&
lw(24p) | cw(24p) | cw(18p) | cw(24p) | cw(18p) | cw(24p) | cw(18p) | cw(24p) | cw(18p) .
Receiving  INFO 0    FE 2 DS 1.1    \(em    \(em    \(em    /    \(em    FE 2\fR DS 1.1    \(em
_
.T&
lw(24p) | cw(24p) | cw(18p) | cw(24p) | cw(18p) | cw(24p) | cw(18p) | cw(24p) | cw(18p) .
Receiving  INFO 3    /    \(em    \(em    FE 4\fR DS 1.5    \(em    \(em    /    /
_
.T&
lw(24p) | cw(24p) | cw(18p) | cw(24p) | cw(18p) | cw(24p) | cw(18p) | cw(24p) | cw(18p) .
Lost framing  at T  (Note\ 1)    /    \(em    \(em    \(em    FE 7\fR DS 1.3    \(em    /    /
_
.T&
lw(24p) | cw(24p) | cw(18p) | cw(24p) | cw(18p) | cw(24p) | cw(18p) | cw(24p) | cw(18p) .
Expiry of timer\ T2    \(em    \(em    \(em    \(em    \(em    \fBFE 7\fR DS 1.7    \(em    \fBFE 7\fR DS 1.0
_
.T&
lw(24p) | cw(24p) | cw(18p) | cw(24p) | cw(18p) | cw(24p) | cw(18p) | cw(24p) | cw(18p) .
Ready to transmit  INFO 2    \(em    \fBFE 7\fR DS 1.2    \(em    \(em    \(em    \(em    \(em    \(em
_
.T&
lw(24p) | cw(24p) | cw(18p) | cw(24p) | cw(18p) | cw(24p) | cw(18p) | cw(24p) | cw(18p) .
 {
Digital section fully activated
 }    \(em    \(em    FE 3 DS 1.3    \(em    \(em    \(em    \(em    \(em
_
.T&
lw(24p) | cw(24p) | cw(18p) | cw(24p) | cw(18p) | cw(24p) | cw(18p) | cw(24p) | cw(18p) .
 {
Digital section fully deactivated
 }    \(em    \(em    \(em    \(em    \(em    FE 6\fR DS 1.8    FE 6\fR DS 1.0    \(em
_
.TE
.nr PS 9
.RT
.ad r
\fBTableau 3/G.960 [1T3.960] \ \
(\*`a l'italienne), p.\fR
.sp 1P
.RT
.ad b
.RT
.LP
.bp
.ce
\fBH.T. [2T3.960]\fR
.ps 9
.vs 11
.nr VS 11
.nr PS 9
.TS
center box;
cw(342p) .
 {
TABLE\ 3/G.960\ \fI(cont.)\fR
 }
.T&
lw(192p) .
.TE
.TS
center box;
cw(24p) | cw(24p) | cw(18p) | cw(24p) | cw(18p) | cw(24p) | cw(18p) | cw(24p) | cw(18p) | cw(48p) .
State number    DS 1.0  \fB(Note 2)\fR    DS 1.1  \fB(Note 2)\fR    DS 1.2  (Note 2)    DS 1.3  (Note 2)    DS 1.5  \fB(Note 2)\fR    DS 1.6  \fB(Note 2)\fR      DS 1.7  (Note 3)    DS 1.8  (Note 3)     {
DS\(hystates related to loopbacks
 }
INFO  sent    INFO 0    INFO 0    INFO 2    INFO 2    INFO 4    INFO 0    INFO 0    INFO 0
_
FE 8
_
FE 9
_
FE 10
FE 11    \fBFE 6\fR DS 3.1    \(em    \(em    Start\ T2 DS 3.6    Start\ T2 DS 3.6    \fBFE 6\fR DS 3.2    \fBFE 6\fR DS 3.1    \fBFE 6\fR DS 3.1
_
.TE
.nr PS 9
.RT
.ad r
\fBRemarques du tableau 3/G.960 [2T3.960], p.\fR
.sp 1P
.RT
.ad b
.RT
.LP
.bp
.sp 2P
.LP
5.4.2
    \fIDescription of the ET layer 1 state transition table\fR
.sp 1P
.RT
.sp 1P
.LP
5.4.2.1
    \fIET layer 1 states (ET\(hystates)\fR
.sp 9p
.RT
.PP
Hereafter are defined the states that the ET layer 1 may enter as a result
of: function elements (FEs) received across reference point\ V\d1\u,
service primitives received (PH\(hy, MPH\(hyprimitives), or internal events.
.PP
The ET\(hystates are classified according to the functionality they
support as follows:
.RT
.LP
    i)
     ET 1.X states for the support of functionality according to Recommendation\
I.430;
.LP
    ii)
     ET 2.X states for the support of functionality related to loopbacks (these
states complement ET 1.X states);
.LP
    iii)
     ET 3.X states for the support of functionality related to digital section
only activation/deactivation (these states complement ET\ 1.X
states).
.sp 1P
.LP
5.4.2.1.1\ \ State ET 1.0: the access (interface at reference point T and
digital section) is in a stable state (deactivated or activated). Timer
T1 is not running.
.sp 9p
.RT
.LP
5.4.2.1.2\ \ State ET 1.1: an activation has been initiated to establish
a call. Timer\ T1 is running.
.LP
5.4.2.1.3\ \ State ET 2.0: the access is in a loopback state. Timer T1 is not
running.
.LP
5.4.2.1.4\ \ State ET 2.1: a loopback request has been issued. Timer T1 is
running.
.LP
5.4.2.1.5\ \ State ET 3.0: the access is in a stable state. The digital
section only is activated while the interface at the T reference point
is deactivated or activated. Timer\ T1 is not running.
.LP
5.4.2.1.6\ \ State ET 3.1: an activation has been initiated to establish
a call. When the activation of the interface at the T\ reference point
was invoked, the digital section was already activated. Timer\ T1 is running.
.LP
5.4.2.1.7\ \ State ET 3.2: this is a transitional state which is entered
when the digital section only activation has been invoked. Timer\ T1 is
running.
.sp 1P
.LP
5.4.2.2
     \fIRepertoire of PH\(hy and MPH\(hyprimitives within ET for the suppport\fR
\fIof functions specified in Recommendations\ I.440 and I.441. They are
related\fR \fIto call control\fR
.sp 9p
.RT
.PP
The repertoire of these primitives is defined in Recommendations
I.430 \(sc\ 6.2.1 and\ I.441 \(sc\ 4.1.
.PP
The MPH\(hyEI primitive used in this Recommendation includes the MPH\(hyEI
primitive as defined in Recommendation\ I.430, \(sc\ 6.2.1.5. In addition,
it
notifies to the system management configuration control an error condition
if the activation or loopback operation attempt failed (see \(sc\ 5.4.2.3).
.RT
.sp 1P
.LP
5.4.2.3
    \fIRepertoire of MPH\(hyprimitives within ET for the support of\fR
\fIfunctions associated with the digital section\fR
.sp 9p
.RT
.PP
The primitives below permit the digital section to change between two modes.
In the first one, full information transfer capability of the
digital
section is available whatever the status of the user\(hynetwork interface at
reference point\ T is. In the second one, full information transfer capability
of the digital section is available only if the user\(hynetwork interface
at
reference point\ T has to be or is activated. They are related to configuration
control.
.RT
.LP
    i)
    MPH\(hyDIGITAl SECTION ACTIVATE\(hyREQUEST (MPH\(hyDSAR)
.LP
    The MPH\(hyDSAR primitive is used to request the digital section to
maintain the full information transfer capability disregarding the
state of the T\ reference point. The configuration control has to make
provision that this primitive is issued only if the access is
deactived.
.bp
.LP
    ii)
    MPH\(hyDIGITAL SECTION ACTIVATE\(hyINDICATION (MPH\(hyDSAI)
.LP
    The MPH\(hyDSAI primitive is used to indicate that the digital section is
in a mode capable to maintain the full information transfer capability
whatever the status of the user\(hynetwork interface at reference point\ T
is.
.LP
    iii)
    MPH\(hyDIGITAL SECTION DEACTIVATE\(hyREQUEST (MPH\(hyDSDR)
.LP
    The MPH\(hyDSDR primitive is used to restore the mode where the status of
the digital section is controlled by those primitives
(PH\(hyACTIVATE\(hyREQUEST, or MPH\(hyACTIVATE\(hyREQUEST as appropriate, and
MPH\(hyDEACTIVATE\(hyREQUEST) which are used for the activation/deactivation
of the interface at reference point\ T. This includes the deactivation
of the digital section if the interface at reference point\ T has
previously been deactivated. The configuration control has to make
provision that this primitive is issued only if the interface at
reference point\ T is deactivated.
.LP
    iv)
    MPH\(hyDIGITAL SECTION DEACTIVATE\(hyINDICATION (MPH\(hyDSDI)
.LP
    This primitive supports a confirmed deactivation service. It is issued
when the digital section is fully deactivated. Depending on
deactivation
procedures the interface at the T\ reference point is already or not
yet deactivated.
.LP
    v)
    MPH\(hyERROR\(hyINDICATION (MPH\(hyEI)
.LP
    The MPH\(hyEI primitive is used to notify the system management if the
activation or loopback operation attempt failed.
.LP
    vi)
    MPH\(hyAWAKE\(hyINDICATION (MPH\(hyAWI)
.LP
    This primitive notifies the network side management that the
activation of the interface at reference point\ T has been invoked by
the user side. It may be used by the ET to assign the resources
required to support layer\ 2.
.PP
The primitives below are associated with maintenance functions
based on loopbacks. The activate request primitives include the activation
of the digital section and possibly the user\(hynetwork interface at reference
point\ T. The establishment of the requested loopback is notified to the
requester by means of the MPH\(hyAI primitive. The deactivation of a loopback
is invoked by means of the MPH\(hyDSDR primitive, or alternatively the
MPH\(hyDR
primitive, as appropriate.
.LP
    MPH\(hyL2AR:
    activation request for loopback 2
.LP
    MPH\(hyL1AR:
    activation request for loopback 1
.LP
    MPH\(hyL1AAR:
    activation request for loopback 1A
.PP
The primitives below are used for other test purposes than
loopbacks (continuidy test).
.sp 9p
.RT
.LP
    MPH\(hyAR:
    activation request of the interface at the
T\ reference point and the digital section for continuity test
purpose.
.LP
    MPH\(hyAI:
    activation indication of the interface at the T
reference point and of the digital section.
.sp 1P
.LP
5.4.2.4
    \fIET layer 1 state transition table\fR
.sp 9p
.RT
.PP
The state transition table, Table 4/G.960, specifies the
procedures. It includes the actions to be taken on various events while in a
specific state (see \(sc\ 5.4.2.1 for the definition of the states). It
specifies the interactions with ET layer\ 2 and system management which
are required to
support the layer interface procedures in accordance with Recommendation\
I.430 (sequences of PH\(hy and MPH\(hyprimitives in compliance with I.430)
and the
interactions across the layer interface between ET layer\ 1 and system
management for the support of functions associated with the digital section
(see \(sc\ 5.4.2.3 for the definition of the related MPH\(hyprimitives).
.RT
.LP
.rs
.sp 4P
.LP
.bp
.ce
\fBH.T. [1T4.960]\fR
.ce
TABLE\ 4/G.960
.ce
\fBState transition table of ET layer 1\fR
.ce
\fB(ET layer 1 state machine)\fR
.ps 9
.vs 11
.nr VS 11
.nr PS 9
.TS
center box;
lw(33p) | cw(27p) | cw(27p) | cw(27p) | cw(33p) | cw(27p) | cw(27p) | cw(27p) .
State  Event    ET 1.0    ET 1.1    ET 2.0    ET 2.1    ET 3.0    ET 3.1    ET 3.2
_
.T&
cw(33p) | cw(27p) | cw(27p) | cw(27p) | cw(33p) | cw(27p) | cw(27p) | cw(27p) .
PH\(hyAR/  MPH\(hyAR    Start\ T1  FE 1  ET 1.1    \(em    PH\(hyDI  \(em    PH\(hyDI  \(em    Start\ T1  FE 1  ET 3.1    \(em    Restart\ T1  FE 1  ET 3.1
_
.T&
cw(33p) | cw(27p) | cw(27p) | cw(27p) | cw(33p) | cw(27p) | cw(27p) | cw(27p) .
MPH\(hyDR    PH\(hyDI  FE 5  \(em    |    FE 5  ET 1.0    |    PH\(hyDI  FE 11  \(em    |    |
_
.T&
cw(33p) | cw(27p) | cw(27p) | cw(27p) | cw(33p) | cw(27p) | cw(27p) | cw(27p) .
FE 2    Start\ T1  MPH\(hyAWI  ET 1.1    (Note 3)  MPH\(hyAWI  \(em    /    \(em    Start\ T1  MPH\(hyAWI  ET 3.1    (Note 3)  MPH\(hyAWI  \(em     {
Restart\ T1
MPH\(hyAWI
ET 3.1
 }
_
.T&
cw(33p) | cw(27p) | cw(27p) | cw(27p) | cw(33p) | cw(27p) | cw(27p) | cw(27p) .
Expiry of timer T1    /    MPH\(hyEI  ET 1.0    /    MPH\(hyEI  ET 1.0    /    MPH\(hyEI  ET 3.0    MPH\(hyEI  ET 1.0
_
.T&
cw(33p) | cw(27p) | cw(27p) | cw(27p) | cw(33p) | cw(27p) | cw(27p) | cw(27p) .
FE 3    (Note 4)  MPH\(hyDSAI  \(em    MPH\(hyDSAI  \(em    To be specified    To be specified    (Note 4)  MPH\(hyDSAI  \(em    MPH\(hyDSAI  \(em    Stop\ T1  MPH\(hyDSAI  ET 3.0
_
.T&
cw(33p) | cw(27p) | cw(27p) | cw(27p) | cw(33p) | cw(27p) | cw(27p) | cw(27p) .
FE 4    (Note 4)  MPH\(hyAI  \(em     {
Stop\ T1
PH\(hyAI
MPH\(hyAI
ET 1.0
 }    To be specified     {
Stop\ T1
MPH\(hyAI
\fBMPH\(hyAI\fR
ET 2.0
 }     {
(Note 4)
\fBMPH\(hyAWI\fR
\(em
 }     {
Stop\ T1
PH\(hyAI
MPH\(hyAI
ET 3.0
 }    /
_
.T&
cw(33p) | cw(27p) | cw(27p) | cw(27p) | cw(33p) | cw(27p) | cw(27p) | cw(27p) .
FE 6    MPH\(hyDSDI  \(em    /    To be specified    To be specified    /    /    /
_
.T&
cw(33p) | cw(27p) | cw(27p) | cw(27p) | cw(33p) | cw(27p) | cw(27p) | cw(27p) .
FE 7    MPH\(hyDI  MPH\(hyEI    /    To be specified    To be specified    MPH\(hyDI  MPH\(hyEI    /    /
_
.T&
cw(33p) | cw(27p) | cw(27p) | cw(27p) | cw(33p) | cw(27p) | cw(27p) | cw(27p) .
MPH\(hyL2AR    Start\ T1  FE 8  ET 2.1    |    |    |    |    |    |
_
.T&
cw(33p) | cw(27p) | cw(27p) | cw(27p) | cw(33p) | cw(27p) | cw(27p) | cw(27p) .
MPH\(hyL1AR    Start\ T1  FE\ 9  TC 2.1    |    |    |    |    |    |
_
.T&
cw(33p) | cw(27p) | cw(27p) | cw(27p) | cw(33p) | cw(27p) | cw(27p) | cw(27p) .
MPH\(hyL1AAR    Start\ T1  FE\ 10  TC 2.1    |    |    |    |    |    |
_
.T&
cw(33p) | cw(27p) | cw(27p) | cw(27p) | cw(33p) | cw(27p) | cw(27p) | cw(27p) .
MPH\(hyDSAR (Note 1)    Start\ T1  FE\ 11  ET 3.2     {
(Note 2)
\fBMPH\(hyAI\fR
ET 3.1
 }    |    |    |    |    |
_
.T&
cw(33p) | cw(27p) | cw(27p) | cw(27p) | cw(33p) | cw(27p) | cw(27p) | cw(27p) .
MPH\(hyDSDR  (Note\ 1)    (Note 5)  FE\ 5   \(em    |    FE\ 5  ET 1.0    |    FE\ 5  ET 1.0    |     {
|
\(em
No state change, no action when event occurs
|
Impossible event by the definition of the layer 1 service
/
Impossible event due to internal reasons or peer\(hyto\(hypeer
procedures
 }
_
.TE
.nr PS 9
.RT
.ad r
\fBTableau 4/G.960 [1T4.960], p.\fR
.sp 1P
.RT
.ad b
.RT
.LP
.bp
.ce
\fBH.T. [2T4.960]\fR
.ce
PH\(hyAI
.ce
Issue PH\(hyACTIVATE\(hyINDICATION primitive
.ce
PH\(hyDI
.ce
Issue PH\(hyDEACTIVATE\(hyINDICATION primitive
.ce
MPH\(hyAWI
.ce
Issue MPH\(hyAWAKE\(hyINDICATION primitive
.ce
\fR
.ce
MPH\(hyAI
.ce
Issue MPH\(hyACTIVATE\(hyINDICATION primitive
.ce
\fR
.ce

.ce
\fR
.ce
MPH\(hyDI
.ce
Issue MPH\(hyDEACTIVATE\(hyINDICATION primitive
.ce
\fR
.ce

.ce
\fR
.ce
MPH\(hyDSDI
.ce
Issue MPH\(hyDIGITAL SECTION DEACTIVATE\(hyINDICATION
.ce
primitive
.ce
MPH\(hyEI
.ce
Issue MPH\(hyERROR\(hyINDICATION primitive
.ce
\fR
.ce
\fR
.ce
FE..
.ce
Issue function element FE.. across V1 reference
point
.ce
ET ab
.ce
Enter state ET a.b
.ce
.LP
\fINote\ 1\fR
\ \(em\ The primitives MPH\(hyDSAR and MPH\(hyDSDR are allowed only if the T
reference point is deactivated. The management has to meet this requirement.
.LP
\fINote\ 2\fR
\ \(em\ This event occurs in the case of a collision between the
MPH\(hyDSAR primitive and the MPH\(hyAWI primitive (or the MPH\(hyDSAI
primitive, if
management ignores the
MPH\(hyAWI primitive) at the boundary between ET layer\ 1 and management. This
collision has been caused by concurrent invokation of digital section only
activation and access activation from the user side.
.LP
\fINote\ 3\fR
\ \(em\ This event occurs in the case of a collision between the function
elements FE 1 and FE 2 at reference point\ V1. This collision has been
caused by concurrent invokation of an activation of the interface from
the user side and network side.
.LP
\fINote\ 4\fR
\ \(em\ These events occur if timer T1 expires concurrently with the
completion of a task which the digital section indicates fo ET layer\ 1 by
means of the appropriate function element (FE 3 and FE 4). It is a situation
caused by excessive delay within the digital section. In some cases it is
advantageous to issue the appropriate primitive to notify to management the
status of the customer access subsequent to the error indication which would
have been conveyed in an MPH\(hyEI primitive. This provides the management with
the information to initiate the optimum recovery procedure.
.LP
\fINote\ 5\fR
\ \(em\ This event occurs if timer T1 expired and management invokes a
deactivation as a consequence of the receipt of the MPH\(hyEI primitive. In
particular this recovery seems to be useful in case of excessive delays (see
Note\ 4).
.ce
\fBH.T. [T5.960]\fR
.ce
TABLE\ 5/G.960
.ce
\fBDefect conditions and consequent actions\fR
.ps 9
.vs 11
.nr VS 11
.nr PS 9
.TS
center box;
cw(36p) | cw(48p) | cw(36p) | cw(54p) sw(54p) , ^  | ^  | c | c | c.
Equipment    Defect  conditions    \fB.\fR    Consequent actions
        FII    Signal at V 1    Signal at T
_
.T&
cw(36p) | lw(48p) | cw(36p) | cw(54p) | cw(54p) .
LT    Excessive error rate (Note 1)    Yes    FFS    FFS
.T&
cw(36p) | lw(48p) | cw(36p) | cw(54p) | cw(54p) .
Line side    Loss of signal    Yes    FE 7 (Note\ 4)    INFO (Note\ 5)
.T&
cw(36p) | lw(48p) | cw(36p) | cw(54p) | cw(54p) .
    Loss of frame    Yes    FE 7 (Note\ 4)    INFO (Note\ 5)
_
.T&
cw(36p) | lw(48p) | cw(36p) | cw(54p) | cw(54p) .
NT    Excessive error rate (Note 1)    Yes    FFS    FFS
.T&
cw(36p) | lw(48p) | cw(36p) | cw(54p) | cw(54p) .
Line side    Loss of signal    Yes    Not applicable    INFO (Note\ 5)
.T&
cw(36p) | lw(48p) | cw(36p) | cw(54p) | cw(54p) .
    Loss of frame    Yes    Not applicable    INFO (Note\ 5)
_
.T&
cw(36p) | lw(48p) | cw(36p) | cw(54p) | cw(54p) .
NT at T    Loss of signal    Yes (Note\ 3)    FE 7 (Note\ 4)    Not applicable  (Note\ 3)
.T&
cw(36p) | lw(48p) | cw(36p) | cw(54p) | cw(54p) .
    Loss of frame    Yes (Note\ 3)    FE 7 (Note\ 4)    Not applicable
_
.T&
cw(36p) | lw(48p) | cw(36p) | cw(54p) | cw(54p) .
NT    Loss of power    Yes (Note\ 2)    FFS     {
INFO 0
FFS
For further study
 }
.TE
.LP
\fINote\ 1\fR
\ \(em\ If processed in the digital section.
.LP
\fINote\ 2\fR
\ \(em\ Depending on power feed arrangements, optional.
.LP
\fINote\ 3\fR
\ \(em\ Optional.
.LP
\fINote\ 4\fR
\ \(em\ This signal is defined in \(sc\ 5.
.LP
\fINote\ 5\fR
\ \(em\ Whether an existing INFO as defined in
Recommendation\ I.430 may be used is for further study.
.nr PS 9
.RT
.ad r
\fBRemarques du tableau 4/G.960 [2T4.960], p.\fR
.sp 1P
.RT
.ad b
.RT
.LP
.sp 3
.sp 1P
.LP
5.4.2.5
    \fIPrimitive procedures for the support of functions specified\fR
\fIin Recommendations I.440 and\ I.441\fR
.sp 9p
.RT
.PP
The sequences of PH\(hy and MPH\(hyprimitives which are valid between ET
layer\ 1 and ET layer\ 2. and ET layer\ 1 and system management, respectively,
for the support of functions specified in Recommendations\ I.440 and\ I.441
and the ET layer\ 1 states as perceived by ET layer\ 2 and system management
as a result of primitives transferred between entities are specified in
Recommendation\ I.430 \(sc\ 6.2.1.6.
.RT
.sp 1P
.LP
5.4.2.6
    \fIPrimitve procedures for the support of functions associated\fR
\fIwith the digital section\fR
.sp 9p
.RT
.PP
The allowed sequences of MPH\(hyprimitives between ET layer 1 and
system management for the support of functions associated with the digital
section are specified in the state transition diagram, Figure\ 7/G.960. This
state transition diagram defines the ET layer\ 1 states that system management
perceives ET layer\ 1 to be in as a result of primitives transferred across
the corresponding layer interface.
.RT
.LP
.rs
.sp 7P
.LP
.bp
.LP
.rs
.sp 47P
.ad r
\fBFigure 7/G.960, p.\fR
.sp 1P
.RT
.ad b
.RT
.LP
.bp
.sp 1P
.LP
5.5
    \fIActivation time\fR
.sp 9p
.RT
.PP
For activation from the user side the activation time is measured at the
T reference point between the initiation of the sending of INFO\ 1 to the
interface at the T\ reference point and the receipt of INFO\ 4 from the
digital section.
.PP
For activation from the network side the activation time is defined
between Functional Element\ 1 and Functional Element\ 4 at the V\d1\ureference
point.
.PP
The activation time is specified for a digital section on which a bit error
rate lower than the value x (see Note\ 1) can be achieved when
activated.
.RT
.sp 1P
.LP
5.5.1
    \fIMaximum activation time (see Note\ 2) for activation occuring\fR
\fIimmediately after a deactivation (without any intervening loopback or\fR
\fIpowering action) (see Note\ 4)\fR :
.sp 9p
.RT
.PP
Metallic pair cable transmission system
.RT
.LP
    i)
    without regenerator:
    300 ms
.LP
    ii)
    with regenerator:
    600 ms
.sp 1P
.LP
5.5.2
    \fIMaximum activation time (see Note 2) for activation occurring\fR
\fIafter the first powering on of a digital section:\fR
.sp 9p
.RT
.LP
    i)
    without regenerator:
    10 sec
.LP
    ii)
    with regenerator:
    10 sec
.PP
\fINote\ 1\fR \ \(em\ The exact test conditions are for further study.
.PP
\fINote\ 2\fR \ \(em\ The specified value for activation time is understood
as a 95%\(hyvalue. This means that for 95% of performed activations the
activation time must be lower than the specified value.
.PP
\fINote\ 3\fR \ \(em\ The values take into account the response time of TE for
sending INFO\ 3 on receipt of INFO\ 2.
.PP
\fINote\ 4\fR \ \(em\ Timer T1 being a functional part of the ET it may be
physically implemented in the ET. In this case, its value may be adjusted
according to the characteristics of the transmission system between the
ET and the digital section when it exists (e.g.\ in case of a satellite
transmission
system a value of 1000\ ms has to be taken into account).
.RT
.sp 2P
.LP
\fB6\fR     \fBOperation and maintenance\fR
.sp 1P
.RT
.sp 1P
.LP
6.1
    \fIGeneral\fR
.sp 9p
.RT
.PP
This paragraph describes the operation and maintenance functions
for the digital section of the ISDN basic rate access. For the time being
only functions for a digital transmission system for a metallic line are
defined.
.PP
Operation functions related to activation/deactivation procedure are specified
in \(sc\ 5.
.PP
Further assumptions regarding the system management are given in\fR
Annex\ A.
.PP
The maintenance functions recommended in I.603 provide the
capability to maintain the digital section to the level of Network Performance
given in \(sc\ 4 of this Recommendation.
.PP
It must be possible to test and maintain the digital section in
accordance with Recommendation\ I.603 regardless of the customer equipment.
.PP
The main features are:
.RT
.LP
    a)
    control of maintenance and test support facilities;
.LP
    b)
    monitoring of the functional elements to provide operating
and performance information and fault condition indications;
.LP
    c)
    maintenance communication facility.
.sp 2P
.LP
6.2
    \fIControl facilities\fR
.sp 1P
.RT
.sp 1P
.LP
6.2.1
    \fILoopbacks\fR
.sp 9p
.RT
.sp 1P
.LP
6.2.1.1
    Loopback implementation
.sp 9p
.RT
.PP
The location and characteristics of loopbacks are defined in
Recommendation\ I.603.
.bp
.RT
.sp 1P
.LP
6.2.1.2
    \fILoopback procedure\fR
.sp 9p
.RT
.PP
The loopbacks are controlled by ET system management.
.PP
A normal call activation request cannot override a request for
loopback\ 1, 1a or\ 2.
.PP
The procedure for loopback operation always starts from the
deactivated state of the digital section.
.PP
One possible sequence is:
.RT
.LP
    a)
    ET generates an operation command for the required
loopback;
.LP
    b)
    ET receives MPH\(hyAI;
.LP
    c)
    ET performs the test;
.LP
    d)
    ET generates a release command;
.LP
    e)
    ET receives MPH\(hyDI.
.sp 1P
.LP
6.2.2
    \fIAuxiliary equipment line\fR
\fIswitchover\fR
.sp 9p
.RT
.PP
The function provides control of switchovers across the V\d1\ureference point:
.RT
.LP
    a)
    to switch the line from the LT to a line measurement
device;
.LP
    b)
    to switch the line from the normal LT to a standby LT;
.LP
    c)
    to switch the LT to test NT1 located in the local
exchange.
.PP
This function is optional. The function definition, control
options and procedures are for further study.
.sp 1P
.LP
6.2.3
    \fIControl of functions in the NT1\fR
.sp 9p
.RT
.PP
This function allows control of specific functions within the NT1 and is
for further study.
.PP
An example of such a function: control of switching between normal and
restricted power at the user network interface.
.RT
.sp 1P
.LP
6.2.4
    \fIInformation request\fR
.sp 9p
.RT
.PP
This function allows the ET to request from the LT, regenerator
and NT1 specific status reports.
.RT
.sp 1P
.LP
6.2.5
    \fIPower switch on/off to the line\fR
.sp 9p
.RT
.PP
This function allows switching of the power to the line, and may
be automatically applied upon reception of a power feed failure
indication.
.RT
.sp 1P
.LP
6.2.6
    \fIContinuity test\fR
.sp 9p
.RT
.PP
The continuity test is described in Recommendation I.603.
.PP
The continuity test is controlled by the ET and is initiated by
MPH\(hyAR. System management decides when the test is passed (i.e. on reception
of MPH\(hyDSAI or MPH\(hyAI). When the system management receives MPH\(hyEI
(expiry T1) the test is considered to be failed. See also Annex\ A to this
Recommendation.
.RT
.sp 2P
.LP
6.3
    \fIMonitoring\fR
.sp 1P
.RT
.sp 1P
.LP
6.3.1
    \fIFunctions\fR
.sp 9p
.RT
.PP
The following operational conditions are monitored throughout the   section:
.RT
.LP
    a)
    the defect conditions;
.LP
    b)
    the power feed arrangements;
.LP
    c)
    transmission performance.
.sp 1P
.LP
6.3.2
    \fIImplementation aspects\fR
.sp 9p
.RT
.PP
Monitoring capabilities must be provided in the digital section
(see Recommendation I.603). The handling and processing of the information
is implementation dependent. For example:
.RT
.LP
    a)
    the use of registers/counters in functional groups, the use
of explicit commands and responses to establish status reports;
.LP
    b)
    the transfer of information to the exchange, either when a
defect condition occurs or on a regular basis. This information is
then processed by entities outside the digital section.
.bp
.sp 2P
.LP
6.3.3
    \fIAnomaly and defect conditions and consequent action\fR
.sp 1P
.RT
.sp 1P
.LP
6.3.3.1
    \fIDefect conditions\fR
.sp 9p
.RT
.PP
The following defect conditions are examples:
.RT
.LP
    i)
    excessive error rate;
.LP
    ii)
    loss of incoming signal;
.LP
    iii)
    loss of frame alignment;
.LP
    iv)
    power feed failure.
.PP
\fINote\fR \ \(em\ One example of an anomaly is a transmission error.
.sp 1P
.LP
6.3.3.2
    \fIConsequent actions\fR
.sp 9p
.RT
.PP
Further to the detection of a defect condition appropriate actions should
be taken as specified in Table 5/G.960.
.PP
Defect indication information (FII) is automatically transmitted
from the digital section to the\ ET.
.RT
.ce
\fBH.T. [T5.960]\fR
.ce
TABLE\ 5/G.960
.ce
\fBDefect conditions and consequent actions\fR
.ps 9
.vs 11
.nr VS 11
.nr PS 9
.TS
center box;
cw(36p) | cw(48p) | cw(36p) | cw(54p) sw(54p) , ^  | ^  | c | c | c.
Equipment    Defect  conditions    \fB.\fR    Consequent actions
        FII    Signal at V 1    Signal at T
_
.T&
cw(36p) | lw(48p) | cw(36p) | cw(54p) | cw(54p) .
LT    Excessive error rate (Note 1)    Yes    FFS    FFS
.T&
cw(36p) | lw(48p) | cw(36p) | cw(54p) | cw(54p) .
Line side    Loss of signal    Yes    FE 7 (Note\ 4)    INFO (Note\ 5)
.T&
cw(36p) | lw(48p) | cw(36p) | cw(54p) | cw(54p) .
    Loss of frame    Yes    FE 7 (Note\ 4)    INFO (Note\ 5)
_
.T&
cw(36p) | lw(48p) | cw(36p) | cw(54p) | cw(54p) .
NT    Excessive error rate (Note 1)    Yes    FFS    FFS
.T&
cw(36p) | lw(48p) | cw(36p) | cw(54p) | cw(54p) .
Line side    Loss of signal    Yes    Not applicable    INFO (Note\ 5)
.T&
cw(36p) | lw(48p) | cw(36p) | cw(54p) | cw(54p) .
    Loss of frame    Yes    Not applicable    INFO (Note\ 5)
_
.T&
cw(36p) | lw(48p) | cw(36p) | cw(54p) | cw(54p) .
NT at T    Loss of signal    Yes (Note\ 3)    FE 7 (Note\ 4)    Not applicable  (Note\ 3)
.T&
cw(36p) | lw(48p) | cw(36p) | cw(54p) | cw(54p) .
    Loss of frame    Yes (Note\ 3)    FE 7 (Note\ 4)    Not applicable
_
.T&
cw(36p) | lw(48p) | cw(36p) | cw(54p) | cw(54p) .
NT    Loss of power    Yes (Note\ 2)    FFS     {
INFO 0
FFS
For further study
 }
.TE
.LP
\fINote\ 1\fR
\ \(em\ If processed in the digital section.
.LP
\fINote\ 2\fR
\ \(em\ Depending on power feed arrangements, optional.
.LP
\fINote\ 3\fR
\ \(em\ Optional.
.LP
\fINote\ 4\fR
\ \(em\ This signal is defined in \(sc\ 5.
.LP
\fINote\ 5\fR
\ \(em\ Whether an existing INFO as defined in
Recommendation\ I.430 may be used is for further study.
.nr PS 9
.RT
.ad r
\fBTable 5/G.960 [T5.960], p.\fR
.sp 1P
.RT
.ad b
.RT
.sp 2P
.LP
6.3.4
    \fIError performance monitoring\fR
.sp 1P
.RT
.sp 1P
.LP
6.3.4.1
    \fIGeneral\fR
.sp 9p
.RT
.PP
Provision has to be made in order to monitor the error performance of the
digital section and to report on such performance.
.bp
.RT
.sp 1P
.LP
6.3.4.2
    \fIError performance parameters\fR
.sp 9p
.RT
.PP
The digital section must deliver to the ET the necessary
information to allow it to evaluate the error performance parameters defined
in Recommendation\ G.821.
.RT
.sp 1P
.LP
6.3.5
    \fIStatus report functions\fR
.sp 9p
.RT
.PP
Status report functions cover information which relate to the
overall operation and performance of the digital section. The information
may be transmitted either automatically or under request of ET.
.PP
Listed below are descriptions of the status report
functions:
.RT
.LP
    i)
    \fITransmission errors\fR
.LP
    This information, derived in the digital section, allows the
ET to evaluate the transmission error performance.
.LP
    ii)
    \fILoopback 1 status\fR
.LP
    This information, sent from the LT, gives the status of
loopback\ 1.
.LP
    iii)
    \fILoopback 1A status\fR
.LP
    This information, sent from the regenerator, gives the
status of loopback\ 1A.
.LP
    iv)
    \fILoopback 2 status\fR
.LP
    This information, sent from the NT1, gives the status of
loopback\ 2.
.LP
    v)
    \fIUser network interface power feed status\fR
.LP
    This information indicates the status of the user network
interface at T\ reference point power feed, e.g.\ normal or restricted
power feed mode.
.LP
    vi)
    \fIUser network interface power feed fault\fR
.LP
    This information indicates a failure of the normal or restricted
power source.
.LP
    This function may be split into two reports.
.LP
    This information is reported on request of the ET.
.LP
    vii)
    \fIUser network interface power feed overload\fR
.LP
    This information indicates that the power drawn from any source
within the NT1 exceeds the maximum power that is available.
.LP
    This information is reported on request of the ET.
.LP
    viii)
    \fIDefect indication information\fR
.LP
    This information is transmitted automatically under conditions
specified in \(sc\ 6.3.3.1.
.ce
\fBH.T. [T6.960]\fR
.ce
TABLE\ 6/G.960
.ce
\fBStatus report functions\fR
.ps 9
.vs 11
.nr VS 11
.nr PS 9
.TS
center box;
cw(84p) | cw(48p) | cw(60p) .
Function    Location    Mandatory/optional
_
.T&
lw(84p) | cw(48p) | cw(60p) .
Transmission errors    LT    M
.T&
lw(84p) | cw(48p) | cw(60p) .
\fB.\fR    REG.    O
.T&
lw(84p) | cw(48p) | cw(60p) .
\fB.\fR    NT    O
.T&
lw(84p) | cw(48p) | cw(60p) .
Loopback 1 status (Note)    LT    M
.T&
lw(84p) | cw(48p) | cw(60p) .
Loopback 1A status (Note)    REG.    M
.T&
lw(84p) | cw(48p) | cw(60p) .
Loopback 2 status (Note)    NT1    M
.T&
lw(84p) | cw(48p) | cw(60p) .
 {
T reference point power feed status
 }    NT1    O
.T&
lw(84p) | cw(48p) | cw(60p) .
 {
T reference point power feed fault
 }    NT1    O
.T&
lw(84p) | cw(48p) | cw(60p) .
 {
T reference point power feed overload
 }    NT1    O
.T&
lw(84p) | cw(48p) | cw(60p) .
FII    LT    M
.T&
lw(84p) | cw(48p) | cw(60p) .
\fB.\fR    REG.    M
.T&
lw(84p) | cw(48p) | cw(60p) .
\fB.\fR    NT    M
.TE
.LP
\fINote\fR
\ \(em\ The information may be implicit (e.g., activation
indication).
.nr PS 9
.RT
.ad r
\fBTableau 6/G.960 [T6.960], p.\fR
.sp 1P
.RT
.ad b
.RT
.LP
.bp
.sp 1P
.LP
6.3.6
    \fISystem dependent status report functions\fR
.sp 9p
.RT
.PP
These status reports will be dependent upon the type of digital
transmission system used and require further study.
.PP
Some examples of a particular system are given in Table 7/G.960.
.RT
.ce
\fBH.T. [T7.960]\fR
.ce
TABLE\ 7/G.960
.ce
\fBSystem dependent status report functions\fR
.ps 9
.vs 11
.nr VS 11
.nr PS 9
.TS
center box;
cw(114p) | cw(42p) .
Function    Location
_
.T&
lw(114p) | cw(42p) .
Line test relay state    LT
.T&
lw(114p) | cw(42p) .
LT test relay state    LT
.T&
lw(114p) | cw(42p) .
Remote power switch state    LT
.T&
lw(114p) | cw(42p) .
Remote power feed    LT
.T&
lw(114p) | cw(42p) .
Induced overvoltage on line    LT
.T&
lw(114p) | cw(42p) .
Abnormal current condition    LT
.T&
lw(114p) | cw(42p) .
Receive eye opening    LT  REG.  NT1
.T&
lw(114p) | cw(42p) .
 {
Echo cancellation coefficients
 }    LT  REG.  NT1
.T&
lw(114p) | cw(42p) .
Battery test    NT
_
.TE
.nr PS 9
.RT
.ad r
\fBTable 7/G.960 [T7.960], p.\fR
.sp 1P
.RT
.ad b
.RT
.sp 2P
.LP
\fB7\fR     \fBControl channel C\fR\(da\fBV\fR\(da\fB1\fR
.sp 1P
.RT
.PP
This control channel provides, for each direction of transmission, the
capability to transfer the commands, status report information and FII.
.PP
Although described as a single channel, the control channel may be
realized by a number of sub\(hychannels which may use different transport
mechanisms (as appropriate to the functions). Even though some of the functions
mentioned in \(sc\ 6 have optional status, the C\dV\\d1\uchannel shall
have the
capability to convey all the control information to allow their
implementation.
.RT
.ce 1000
ANNEX\ A
.ce 0
.ce 1000
(to Recommendation G.960)
.sp 9p
.RT
.ce 0
.ce 1000
\fBSYSTEM\ MANAGEMENT\ REQUIREMENTS\fR
.sp 1P
.RT
.ce 0
.LP
A.1
    \fIIntroduction\fR
.sp 1P
.RT
.PP
This Recommendation specifies the required functions of the digital section
and the ET layer\ 1. In order to ensure correct operation, it is
necessary to take into account the assumptions made about the management
functions involved. It is assumed that the structure of the management is as
given in CCITT Recommendation\ Q.940.
.PP
In this Recommendation, distinction is made between ET layer 1 and
system management only. Where the term system management is used it corresponds
to both system management and layer management as defined in
Recommendation\ Q.940.
.bp
.RT
.sp 2P
.LP
A.2
    \fISystem management requirements\fR
.sp 1P
.RT
.sp 1P
.LP
A.2.1
    \fIGeneral\fR
.sp 9p
.RT
.PP
System management shall not initiate more than one action at a time towards
the ET layer\ 1. An action is delimited by the primitive which is issued
by system management and the corresponding primitive which confirms completion
of the task.
.RT
.sp 1P
.LP
A.2.2
    \fIError indications\fR
.sp 9p
.RT
.PP
The management entity takes account of the sequence of primitives before
and after the reception of MPH\(hyEI. From the sequence of the primitives,
the system management may determine the cause of the MPH\(hyEI primitive
(e.g.\ unsuccessful activation of the interface, unsuccessfull activation
of the access, loss of synchronization or signal at the interface at reference
point\ T).
.PP
Upon the occurence of an error, the ET layer shall notify this event to
the system management by means of the primitive MPH\(hyEI. The system
management must decide which appropriate actions should be taken (e.g.\
hold or abandon call, initiate MPH\(hyDR or MPH\(hyDSDR).
.RT
.sp 1P
.LP
A.2.3
    \fILoopback operations\fR
.sp 9p
.RT
.PP
The system management should take into account that when the ET
layer\ 1 is in loopback operation it does not send any primitives to ET
layer\ 2.
.PP
If a primitive is sent by ET layer 2 to ET layer 1 during loopback
operation, it will be ignored by ET layer\ 1.
.PP
The setting of a loopback is initiated by the system management by
issuing a primitive MPH\(hyLxAR where by x\ indicates the type of loopback\
2, 1
or\ 1A.
.PP
The setting of the loopbacks 1, 2 and 1A is confirmed to the system
management by means of the MPH\(hyAI primitive. The system management should be
able to interpret this MPH\(hyAI as a loopback confirmation and not as a normal
activation indication by taking into account the sequence of the
primitives.
.RT
.sp 1P
.LP
A.2.4
    \fIContinuity test\fR
.sp 9p
.RT
.PP
The continuity test is initiated by the system management using the primitive
MPH\(hyAR. The system management must decide when the test is passed
(i.e.\ on reception of MPH\(hyDSAI or MPH\(hyAI). If the system management
receives
MPH\(hyEI (expiry T1) the test is considered to be failed.
.PP
If the test is passed, the system management should check whether a
call establishment has been progressed or if there is a call available
before sending MPH\(hyDR.
.RT
.sp 1P
.LP
A.2.5
    \fIInformation to be sent in the D channel during loopback\fR
\fIoperation\fR
.sp 9p
.RT
.PP
The information sent in the D channel should not imitate any HDLC pattern.
However, it is in the responsibility of the system management to
decide to send the required pattern for fault localisation.
.RT
.sp 1P
.LP
A.2.6
    \fIConfiguration control\fR
.sp 9p
.RT
.PP
The system management shall ensure that any action related to
configuration control will be issued only when the T\ reference point is
deactivated.
.RT
.ce 1000
ANNEX\ B
.ce 0
.ce 1000
(to Recommendation G.960)
.sp 9p
.RT
.ce 0
.ce 1000
\fBVocabulary of terms used in connection with\fR
.sp 1P
.RT
.ce 0
.ce 1000
\fBRecommendations I.430, I.431, G.960 and G.961\fR
.ce 0
.LP
    \fBIntroduction\fR
.sp 1P
.RT
.PP
This Annex provides a vocabulary of terms and definitions that are appropriate
to layer 1 aspects of the ISDN customer access for basic access and primary
rate access.
.bp
.PP
It should be considered in relation to Recommendations\ I.430, I.431, G.960
and\ G.961 since its scope is limited to these Recommendations. It is
provided for a clear understanding of these Recommendations and will be
reviewed during the next Study Period for alignment with Recommendations
produced by other bodies.
.PP
A small number of terms in this Annex are duplicated in other
Recommendations (e.g.\ Recommendation\ I.112 and/or Recommendation\ G.701).
References to these are given in parenthesis as an aid to ensuring consistency
between the Recommendations in the event of future amendments (e.g.\ \*Qcomplete
loopback { .12 } *U). Where the term is defined differently, but the spirit
is
maintained, the reference is shown as in the following example: \*Qfunctional
group  { .112,\ 41 } \*U.
.PP
According to the conventions applied in this Annex any term in common usage,
but whose use is deprecated in the sense defined, is shown after the
recommended term as in the following example: \*Qline [loop]\*U.
.PP
Where a truncated term is widely used in an understood context the
complete term is quoted following the colloquial form, for example: \*Qmultiplex,
digital multiplex equipment\*U.
.PP
Paragraph\ B.7 contains an alphabetical list of all of the terms
contained in this Recommendation.
.PP
Paragraph B.8 illustrates the general aspects of the terminology.
.PP
Paragraph B.9 explains the V reference point, V interface, and
interface point concept.
.RT
.sp 2P
.LP
B.1
    \fIGeneral\fR
.sp 1P
.RT
.sp 1P
.LP
101
    \fBbasic access, basic rate access\fR
.sp 9p
.RT
.PP
A user\(hynetwork access arrangement that corresponds to the
interface structure composed of two B\(hychannels and one D\(hychannel.
The bit rate of the D\(hychannel for this type of access is 16\ kbit/s.
.RT
.sp 1P
.LP
102
    \fBprimary rate access\fR
.sp 9p
.RT
.PP
A user\(hynetwork access arrangement that corresponds to the primary rates
of 1544\ kbit/s and 2048\ kbit/s. The bit rate of the D\(hychannel for
this
type of access is 64\ kbit/s. The typical primary rate interface structures
are as given in Recommendations\ I.412 and I.431.
.RT
.sp 1P
.LP
103
    \fBlocal exchange, ISDN local exchange\fR
.sp 9p
.RT
.PP
The exchange which, in addition to the switching function,
contains the exchange termination for the ISDN customer accesses.
.RT
.sp 1P
.LP
104
    \fBline termination (LT)\fR \fB(abbreviated)\fR
.sp 9p
.RT
.PP
The functional group containing at least the transmit and receive functions
terminating one end of a digital transmission system.
.RT
.sp 1P
.LP
105
    \fBexchange termination (ET)\fR \fB(abbreviated)\fR
.sp 9p
.RT
.PP
The functional group containing at least the layer 2 and layer 3 network
side functions of the I.420 interface at the T reference point.
.PP
\fINote 1\fR \ \(em\ This may not be true if concentrators or other intelligent
equipment are located in the local line distribution network.
.PP
\fINote 2\fR \ \(em\ The ET is not the switching function. The extent to
which the ET supports call control processing and management is not defined.
.RT
.sp 1P
.LP
106
    \fBnetwork termination (NT)\fR \fB(abbreviated)\fR
.sp 9p
.RT
.PP
The functional group on the network side of a user\(hynetwork
interface.
.PP
\fINote\fR \ \(em\ In Recommendations\ I.430 and\ I.431, \*QNT\*U is used
to indicate network terminating layer\ 1 aspects of NT1 and NT2 functional
groups.
.bp
.RT
.sp 1P
.LP
107
    \fBterminal equipment (TE)\fR \fB(abbreviated)\fR
.sp 9p
.RT
.PP
The functional group on the user side of a user network
interface.
.PP
\fINote\fR \ \(em\ In Recommendations I.430 and I.431, \*QTE\*U is used
to indicate terminal terminating layer\ 1 aspects of TE1, TA and NT2 functional
groups.
.RT
.sp 1P
.LP
108
    \fBfunctional group\fR  { .112, 41 }
.sp 9p
.RT
.PP
A set of functions that may be performed by a single equipment.
.PP
\fINote 1\fR \ \(em\ The transmission medium is not part of any functional
group.
.PP
\fINote 2\fR \ \(em\ Regenerators, multiplexers and concentrators are functional
groups which are outside the scope of Recommendation\ I.411.
.RT
.sp 1P
.LP
109
    \fBaccess connection element [subscriber access]\fR  { .32 }
.sp 9p
.RT
.PP
The equipment providing the concatenation of functional groups
between and including the exchange termination and the NT1. The term should
be qualified by the type of access supported. That is:
.RT
.LP
    \(em
    basic access connection element
.LP
    \(em
    primary rate access connection element.
.sp 1P
.LP
110
    \fBcustomer equipment [subscriber installation]\fR  { .32 }
.sp 9p
.RT
.PP
The concatenation of equipment on the user side of the T reference point
(i.e.\ TAs, TE2s, TE1s NT2 and associated transmission media). In the case
of multiple access, the customer equipment includes all the equipment on
the
user side of all those accesses comprising the multiple access.
.PP
\fINote 1\fR \ \(em\ This term should not imply or restrict ownership or
responsibility for providing equipment.
.PP
\fINote 2\fR \ \(em\ The terms \*Quser equipment\*U and \*Qsubscriber equipment\*U
are deprecated.
.RT
.sp 1P
.LP
111
    \fBISDN customer access [ISDN subscriber access]\fR
.sp 9p
.RT
.PP
The equipment providing the concatenation of all functional groups relevant
to an individual or group of related access connection elements
(i.e.\ customer equipment and access connection element).
.PP
\fINote\fR \ \(em\ This term should not imply or restrict ownership or
responsibility for providing equipment.
.RT
.sp 1P
.LP
112
    \fBdirect access, direct access connection element\fR
.sp 9p
.RT
.PP
A specific access connection element in which the basic access
digital section or primary rate access digital section is directly connected
to the exchange termination at a V\d1\uor \d3\ureference point
respectively.
.RT
.sp 1P
.LP
113
    \fBremote access, remote access connection element\fR
.sp 9p
.RT
.PP
A specific access connection element in which the digital section is not
directly connected to the exchange termination but is connected through
a multiplexer or concentrator.
.RT
.sp 1P
.LP
114
    \fBreference point\fR { .112, 42 }
.sp 9p
.RT
.PP
A conceptual point at the conjunction of two non\(hyoverlapping
functional groups.
.PP
\fINote\fR \ \(em\ Each reference point is assigned a prefix letter, for
example: T\ reference point.
.bp
.RT
.sp 1P
.LP
115
    \fBinterface, physical interface\fR { .112, 408; G.701, 100 }
.sp 9p
.RT
.PP
The common boundary between physical equipment.
.RT
.sp 1P
.LP
116
    \fBuser network interface [customer network interface]\fR { .112, 40 }
.sp 9p
.RT
.PP
An interface, at which the access protocols apply, and which is
located at the S\ or T\ reference point.
.RT
.sp 1P
.LP
117
    \fBV interface\fR
.sp 9p
.RT
.PP
A digital interface which usually coincides with the V reference   point.
.PP
\fINote\ 1\fR \ \(em\ A specific V interface is denoted by a suffix number.
.PP
\fINote\ 2\fR \ \(em\ The V interfaces are internal network interfaces.
.RT
.sp 1P
.LP
118
    \fBV\fR\(da\fB1 reference point\fR
.sp 9p
.RT
.PP
A V reference point at the network side of a basic access digital section
for the provision of a single basic access.
.PP
\fINote\fR \ \(em\ The V\d1\uinterface is a functional boundary between the
exchange termination and the line termination and may or may not exist as a
physical interface. The V\d1\uinterface structure is comprised of two
B\(hychannels, one D\(hychannel, and a C\dv\\d1\u\(hychannel.
.RT
.sp 1P
.LP
119
    \fBV\fR\(da\fB2 reference point\fR
.sp 9p
.RT
.PP
A V reference point at the network side of a concentrator for the provision
of a number of basic and/or primary rate accesses.
.RT
.sp 1P
.LP
120
    \fBV\fR\(da\fB3 reference point\fR
.sp 9p
.RT
.PP
A V reference point at the network side of a primary rate access digital
section for the provision of a single primary rate access.
.RT
.sp 1P
.LP
121
    \fBV\fR\(da\fB4 reference point\fR
.sp 9p
.RT
.PP
A V reference point at the network side of a multiplexer
supporting several basic access digital sections.
.RT
.sp 2P
.LP
B.2
    \fIDigital transmission\fR
.sp 1P
.RT
.sp 1P
.LP
201
    \fBDigital link, digital transmission link\fR  { .112, 302; G.701,
300 }
.sp 9p
.RT
.PP
The whole of the means of digital transmission of a digital signal of specified
rate between specified reference points.
.PP
\fINote\fR \ \(em\ A digital link comprises one or more digital sections
and may include either a multiplexer or concentrator, but not switching.
.RT
.sp 1P
.LP
202
    \fBdigital access link\fR
.sp 9p
.RT
.PP
A digital link between the T reference point and the V reference point
in the case of remote access only.
.RT
.sp 1P
.LP
203
    \fBdigital section [section]\fR  { .701, 300 }
.sp 9p
.RT
.PP
The whole of the means of digital transmission of a digital signal of specified
rate between two consecutive reference points. The term should be qualified
by the type of access supported, or by a prefix denoting the
V\ interface at the digital section boundaries. For example:
.RT
.LP
    \(em
    basic access digital section;
.LP
    \(em
    primary rate access digital section;
.LP
    \(em
    V\dx\udigital section.
.bp
.sp 1P
.LP
204
    \fBdigital section boundaries\fR
.sp 9p
.RT
.PP
The reference points at the near and far ends of the digital
section.
.RT
.sp 1P
.LP
205
    \fBdigital system, digital transmission system [system]\fR  { .701,
301 }
.sp 9p
.RT
.PP
A specific means of providing a digital section.
.PP
\fINote\fR \ \(em\ For a specific type of system this term may be qualified
by the insertion of the name of the transmission medium employed by that
specific system. Some examples are:
.RT
.LP
    \(em
    digital line transmission system;
.LP
    \(em
    digital radio system;
.LP
    \(em
    digital optical transmission system.
.sp 1P
.LP
206
    \fBtransmission method\fR
.sp 9p
.RT
.PP
The technique by which the transmission system transmits and
receives signals via the transmission medium.
.RT
.sp 1P
.LP
207
    \fBecho cancellation\fR
.sp 9p
.RT
.PP
A transmission method used in digital transmission systems in
which bi\(hydirectional transmission occurs simultaneously on the same
line and in the same frequency band. An echo canceller is required to attenuate
the echo of the near\(hyend transmission.
.RT
.sp 1P
.LP
208
    \fBtime compression multiplex [burst mode]\fR
.sp 9p
.RT
.PP
A transmission method used in digital transmission systems in
which bi\(hydirectional transmission occurs in non\(hyoverlapping uni\(hydirectional
bursts.
.RT
.sp 1P
.LP
209
    \fBmultiplex, digital multiplex equipment\fR  { .701, 401 }
.sp 9p
.RT
.PP
The combination of a digital multiplexer and a digital
demultiplexer at the same location, operating in opposite directions of
transmission.
.RT
.sp 1P
.LP
210
    \fBstatic multiplex [fixed multiplex]\fR
.sp 9p
.RT
.PP
A multiplex where each tributary channel is assigned to one or
more main\(hystream time\(hyslots and the assignment is fixed.
.RT
.sp 1P
.LP
211
    \fBdynamic multiplex [statistical multiplex]\fR
.sp 9p
.RT
.PP
A multiplex where signalling information of some or all tributary D\(hychannels
is assigned to a lesser number of main\(hystream time\(hyslots on a
statistical basis, but the assignment of other channels is fixed.
.RT
.sp 1P
.LP
212
    \fBconcentrator, digital concentrator\fR
.sp 9p
.RT
.PP
Equipment containing the means to combine, in one direction, a
number of basic accesses, and/or primary rate accesses into a lesser number
of time\(hyslots by omitting the idle channels and/or redundancy, and to
perform the corresponding separation in the contra\(hydirection.
.RT
.sp 2P
.LP
B.3
    \fISignalling\fR
.sp 1P
.RT
.sp 1P
.LP
301
    \fBINFO\fR
.sp 9p
.RT
.PP
A defined layer 1 signal with specified meaning and coding at a
basic access user\(hynetwork interface.
.bp
.RT
.sp 1P
.LP
302
    \fBSIG\fR
.sp 9p
.RT
.PP
A signal representing an exchange of layer 1 information between line terminations
of a digital transmission system for basic access.
.RT
.sp 1P
.LP
303
    \fBfunction elements (FEs)\fR \fB(abbreviated)\fR
.sp 9p
.RT
.PP
A signal representing a functional exchange of layer 1 information at the
V\d1\uinterface.
.RT
.sp 1P
.LP
304
    \fBcontrol channel; C\(hychannel [service channel]\fR
.sp 9p
.RT
.PP
Additional dedicated transmission capability provided at a
reference point or interface, or transported by a digital transmission
system, to support the execution of management functions.
.PP
\fINote\fR \ \(em\ The control channel at a specific reference point, interface
or type of transmission system is denoted by an appropriate suffix. For
example:
.RT
.LP
    \(em
    C\dv\\d1\u:
    channel \(em the control channel at the V\d1\uinterface
.LP
    \(em
    C\dL\u:
    channel \(em the control channel at the
line.
.sp 2P
.LP
B.4
    \fIActivation/deactivation\fR
.sp 1P
.RT
.sp 1P
.LP
401
    \fBdeactivation\fR
.sp 9p
.RT
.PP
A function which places a system, or part of a system, into a
non\(hyoperating or partially operating mode where the power consumption of the
system may be decreased (low power consumption mode).
.RT
.sp 1P
.LP
402
    \fBactivation\fR
.sp 9p
.RT
.PP
A function which places a system, or part of a system, which may have been
in a low power consumption mode during deactivation, into its fully operating
mode.
.RT
.sp 1P
.LP
403
    \fBpermanent activation\fR
.sp 9p
.RT
.PP
Activation of a system, or part of a system, that will not be
deactivated even when it is not required to be fully operating.
.RT
.sp 1P
.LP
404
    \fBline activation\fR
.sp 9p
.RT
.PP
The function which requires the digital line transmission system to be
activated but which may also activate the user\(hynetwork interface.
.RT
.sp 1P
.LP
405
    \fBline\(hyonly activation\fR
.sp 9p
.RT
.PP
The function which requires the activation of only the digital
line transmission system and does not activate the user\(hynetwork
interface.
.RT
.sp 1P
.LP
406
    \fBone\(hystep activation\fR
.sp 9p
.RT
.PP
A type of activation which invokes a sequence of actions to
activate the digital line transmission system and user\(hynetwork interface
from a single command.
.RT
.sp 1P
.LP
407
    \fBtwo\(hystep activation\fR
.sp 9p
.RT
.PP
A type of activation which is initiated by one command to invoke a sequence
of actions to activate the digital line transmission system and
continued by a second command to invoke a sequence of actions to activate
the user\(hynetwork interface.
.bp
.RT
.sp 1P
.LP
408
    \fBone\(hystep deactivation\fR
.sp 9p
.RT
.PP
Deactivation of the digital line transmission system and
user\(hynetwork interface invoked by a single command.
.RT
.sp 1P
.LP
409
    \fBuser\(hynetwork interface only deactivation\fR
.sp 9p
.RT
.PP
Deactivation of the user\(hynetwork interface which does not
deactivate the digital line transmission system.
.RT
.sp 2P
.LP
B.5
    \fILoopbacks\fR
.sp 1P
.RT
.sp 1P
.LP
501
    \fBloopback, digital loopback\fR { .12 } \fB[test loop]\fR  { .112  }
.sp 9p
.RT
.PP
A mechanism incorporated into a piece of equipment whereby a
bi\(hydirectional communication path may be connected back on itself so
that some or all of the information contained in the bit stream sent on
the transmit path is returned on the receive path.
.RT
.sp 1P
.LP
502
    \fBloopback type\fR
.sp 9p
.RT
.PP
The characteristic of a loopback which specifies the relationship between
information entering the loopback and the information leaving the
loopback in the contra\(hydirection.
.RT
.sp 1P
.LP
503
    \fBcomplete loopback\fR { .12 }
.sp 9p
.RT
.PP
A physical layer 1 mechanism which operates on the full bit
stream. At the loopback point, the receive bit stream shall be transmitted
back towards the transmitting station without modification.
.PP
\fINote\fR \ \(em\ The use of the term \*Qcomplete loopback\*U is not related
to
implementation since such a loopback may be provided by means of active
logic elements or controlled unbalance of a hybrid transformer,\ etc. At
the control point only the information channels may be available.
.RT
.sp 1P
.LP
504
    \fBpartial loopback\fR { .12 } \fB[echoing loopback]\fR
.sp 9p
.RT
.PP
A physical layer 1 mechanism which operates on one or more
specified channels multiplexed within the full bit stream. At the loopback
point, the received bit stream associated with the specified channel(s)
shall be transmitted back towards the transmitting station without
modification.
.RT
.sp 1P
.LP
505
    \fBlogical loopback\fR { .12 }
.sp 9p
.RT
.PP
A loopback which acts selectively on certain information within a specified
channel or channels and may result in some specified modification of the
looped information. Logical loopbacks may be defined to apply at any layer,
depending on the detailed maintenance procedures specified.
.RT
.sp 1P
.LP
506
    \fBloopback point\fR  { .12 }
.sp 9p
.RT
.PP
The precise location of the loopback.
.RT
.sp 1P
.LP
507
    \fBloopback control mechanism [control mechanism]\fR { .12 }
.sp 9p
.RT
.PP
The means by which the loopback is operated and released from the loopback
control point.
.RT
.sp 1P
.LP
508
    \fBloopback control point [control point]\fR { .12 }
.sp 9p
.RT
.PP
The point which has the ability to directly control loopbacks. The loopback
control point may receive requests for loopback operation from several
loopback requesting points.
.RT
.sp 1P
.LP
509
    \fBloopback requesting point\fR  { .12 }
.sp 9p
.RT
.PP
The point which requests the loopback control point to operate
loopbacks.
.bp
.RT
.sp 1P
.LP
510
    \fBloopback application\fR { .12 }
.sp 9p
.RT
.PP
The maintenance phase for which the loopback operation is
used.
.RT
.sp 1P
.LP
511
    \fBforward signal\fR
.sp 9p
.RT
.PP
The signal transmitted beyond the loopback point.
.PP
\fINote\fR \ \(em\ The forward signal may be a defined signal or
unspecified.
.RT
.sp 1P
.LP
512
    \fBloopback test pattern\fR  { .12 }
.sp 9p
.RT
.PP
The information transmitted during the operation of the loopback in the
channel or channels which are to be redirected by the loopback.
.RT
.sp 1P
.LP
513
    \fBtransparent loopback\fR { .12 }
.sp 9p
.RT
.PP
A transparent loopback is one in which the signal transmitted
beyond the loopback point (the forward signal) when the loopback is activated,
is the same as the received signal at the loopback point. See
Figure
B\(hy1/G.960.
.RT
.LP
.rs
.sp 12P
.ad r
\fBFigure B\(hy1/G.960, p.\fR
.sp 1P
.RT
.ad b
.RT
.sp 1P
.LP
514
    \fBnon\(hytransparent loopback\fR { .12 }
.sp 9p
.RT
.PP
A non\(hytransparent loopback is one in which the signal transmitted beyond
the loopback point (the forward signal) when the loopback is activated
is not the same as the received signal at the loopback point. The forward
signal may be a defined signal or unspecified. See Figure\ B\(hy2/G.960.
.RT
.LP
.rs
.sp 13P
.ad r
\fBFigure B\(hy2/G.960, p.\fR
.sp 1P
.RT
.ad b
.RT
.LP
.bp
.sp 2P
.LP
B.6
    \fIlocal line distribution network\fR
.sp 1P
.RT
.sp 1P
.LP
601
    \fBlocal line distribution network\fR
.sp 9p
.RT
.PP
A network of cables and wires which are currently installed
between a local exchange and customer premises.
.RT
.sp 1P
.LP
602
    \fBtwisted pair\fR
.sp 9p
.RT
.PP
A line or part of a line which has each (insulated) conductor
twisted around the other to reduce the effect of induction from stray
electromagnetic and/or electrostatic fields.
.PP
\fINote\fR \ \(em\ This definition also applies to twisted quad except
that two pairs are twisted together.
.RT
.sp 1P
.LP
603
    \fBexchange cable\fR
.sp 9p
.RT
.PP
A cable forming part of the local line distribution network, used in the
local exchange between the line termination and main distribution
frame.
.RT
.sp 1P
.LP
604
    \fBmain cable\fR
.sp 9p
.RT
.PP
A cable used in the local line distribution network between the
main distribution frame and a cross connection point.
.RT
.sp 1P
.LP
605
    \fBdistribution cable\fR
.sp 9p
.RT
.PP
A cable used in the local line distribution network between the
cross connection point and a distribution point.
.RT
.sp 1P
.LP
606
    \fBinstallation cable [subscriber cable]\fR
.sp 9p
.RT
.PP
A cable or single pair of metallic wires used in the local line
distribution point and the customer premises.
.RT
.sp 1P
.LP
607
    \fBbridged tap\fR
.sp 9p
.RT
.PP
A length of unused open circuit line that is \*QT\*Ued to the customer
line to provide flexibility in the local line distribution network.
.PP
\fINote\fR \ \(em\ Bridged taps are not used in all local line distribution
networks.
.RT
.sp 1P
.LP
608
    \fBopen wire\fR
.sp 9p
.RT
.PP
A pair of suspended and often uninsulated metallic wires which run parallel
to each other.
.PP
\fINote\fR \ \(em\ Overhead installation cables in common use between
distribution poles and customer premises are not open wires.
.RT
.sp 1P
.LP
609
    \fBloading coil\fR
.sp 9p
.RT
.PP
A device used to modify the electric characteristics of a line
to give relatively constant attenuation over the voice\(hyfrequency range,
but which gives relatively high attenuation beyond that range.
.bp
.RT
.sp 1P
.LP
610
    \fBcrosstalk\fR
.sp 9p
.RT
.PP
A phenomenon by which an unwanted signal is introduced into a line through
coupling to one or more other lines.
.RT
.sp 1P
.LP
611
    \fBintrasystem crosstalk\fR
.sp 9p
.RT
.PP
Crosstalk between lines sharing the same cable on which the same type of
transmission system is used on each line.
.RT
.sp 1P
.LP
612
    \fBintersystem crosstalk\fR
.sp 9p
.RT
.PP
Crosstalk between lines sharing the same cable and on which
different types of transmission systems are used on each line.
.RT
.sp 1P
.LP
613
    \fBnear\(hyend crosstalk (NEXT)\fR \fB(abbreviated)\fR
.sp 9p
.RT
.PP
Crosstalk where the coupling is occurring at or near to the
transmitter.
.RT
.sp 1P
.LP
614
    \fBfar\(hyend crosstalk (FEXT)\fR \fB(abbreviated)\fR
.sp 9p
.RT
.PP
Crosstalk where the coupling is occurring at or near to the end of the
line furthest from the transmitter.
.RT
.sp 1P
.LP
615
    \fBline [loop]\fR
.sp 9p
.RT
.PP
The transmission medium between line terminations. The term may be qualified
by the type of medium used, for example:
.RT
.LP
    \(em
    metallic\ line:
    a pair of metallic (usually copper)
wires,
.LP
    \(em
    optical\ line:
    one optical fibre (bi\(hydirectional
transmission), or one pair of fibres
(uni\(hydirectional transmission).
.sp 1P
.LP
616
    \fBlocal line [subscriber line]\fR
.sp 9p
.RT
.PP
An individual line which is continuous between the line
termination (LT) and the customer premises, passing through the exchange,
main, distribution and installation cables.
.RT
.sp 1P
.LP
617
    \fBdigital local line\fR
.sp 9p
.RT
.PP
A local line which is used by a digital transmission system.
.PP
\fINote\fR \ \(em\ Regenerators are not part of the line but may be inserted
between two line lengths.
.bp
.RT
.sp 2P
.LP
B.7
    \fIAlphabetical list of terms contained in this Annex\fR
.sp 1P
.RT
.sp 1P
.LP
109
    access connection element
.sp 9p
.RT
.LP
\fR 402
    activation
.LP
101
    basic access
.LP
101
    basic rate access
.LP
607
    bridged tap
.LP
208
    [burst mode]
.LP
304
    C\(hychannel
.LP
503
    complete loopback
.LP
212
    concentrator
.LP
304
    control channel
.LP
507
    [control mechanism]
.LP
508
    [control point]
.LP
610
    crosstalk
.LP
110
    customer equipment
.LP
116
    [customer network interface]
.LP
401
    deactivation
.LP
202
    digital access link
.LP
212
    digital concentrator
.LP
201
    digital link
.LP
617
    digital local line
.LP
501
    digital loopback
.LP
209
    digital multiplex equipment
.LP
203
    digital section
.LP
204
    digital section boundaries
.LP
205
    digital system
.LP
201
    digital transmission link
.LP
205
    digital transmission system
.LP
112
    direct access
.LP
112
    direct access connection element
.LP
605
    distribution cable
.LP
211
    dynamic multiplex
.LP
207
    echo cancellation
.LP
504
    [echoing loopback]
.LP
603
    exchange cable
.LP
105
    exchange termination (ET) (abbreviated)
.LP
614
    far\(hyend crosstalk (FEXT) (abbreviated)
.LP
210
    [fixed multiplex]
.LP
511
    forward signal
.LP
303
    function element [FEs) (abbreviated)
.LP
108
    functional group
.LP
301
    INFO
.LP
606
    installation cable
.LP
115
    interface
.LP
612
    intersystem crosstalk
.LP
611
    intrasystem crosstalk
.LP
111
    ISDN customer access
.LP
103
    ISDN local exchange
.LP
111
    [ISDN subscriber access]
.LP
615
    line
.LP
404
    line activation
.LP
405
    line\(hyonly activation
.LP
104
    line termination (LT) (abbreviated)
.LP
609
    loading coil
.LP
103
    local exchange
.LP
616
    local line
.LP
601
    local line distribution network
.LP
505
    logical loopback
.LP
615
    [loop]
.LP
501
    loopback
.LP
510
    loopback application
.LP
507
    loopback control mechanism
.LP
508
    loopback control point
.LP
506
    loopback point
.LP
509
    loopback requesting point
.LP
512
    loopback test pattern
.LP
502
    loopback type
.LP
604
    main cable
.LP
209
    multiplex
.LP
613
    near\(hyend crosstalk (NEXT) (abbreviated)
.LP
106
    network termination (NT) (abbreviated)
.LP
514
    non\(hytransparent loopback
.LP
406
    one\(hystep activation
.LP
408
    one\(hystep deactivation
.LP
608
    open wire
.LP
504
    partial loopback
.LP
403
    permanent activation
.LP
115
    physical interface
.LP
102
    primary rate access
.LP
114
    reference point
.LP
113
    remote access
.LP
113
    remote access connection element
.LP
203
    [section]
.LP
304
    [service channel]
.LP
302
    SIG
.LP
210
    static multiplex
.LP
211
    [statistical multiplex]
.LP
109
    [subscriber access]
.LP
606
    [subscriber cable]
.LP
110
    [subscriber installation]
.LP
616
    [subscriber line]
.LP
205
    [system]
.LP
107
    terminal equipment; (TE) (abbreviated)
.LP
208
    time compression multiplex
.LP
206
    transmission method
.LP
513
    transparent loopback
.LP
602
    twisted pair
.LP
407
    two\(hystep activation
.LP
116
    user\(hynetwork interface
.LP
409
    user\(hynetwork interface only deactivation
.LP
117
    V interface
.LP
118
    V\d1\ureference point
.LP
119
    V\d2\ureference point
.LP
120
    V\d3\ureference point
.LP
121
    V\d4\ureference point
.LP
.bp
.sp 2P
.LP
B.8
    \fIIllustration of the general aspects of the terminology ISDN\fR
\fIcustomer access\fR
.sp 1P
.RT
.LP
.rs
.sp 47P
.ad r
\fBFigure B\(hy3/G.960, p.\fR
.sp 1P
.RT
.ad b
.RT
.LP
.bp
.sp 2P
.LP
B.9
    \fIClarification of the V reference point, V interface,\fR
\fIand interface point concept\fR
.sp 1P
.RT
.PP
B.9.1
The V\d1\ureference point and the V\d3\ureference point are
always on the network side of the line termination and are applicable to
individual (low order) accesses.
.sp 9p
.RT
.PP
A reference point, when physically realized by an interface,
requires the specification of at least two interface points. See
Figure\ B\(hy4/G.960.
.LP
.rs
.sp 10P
.ad r
\fBFigure B\(hy4/G.960, p.\fR
.sp 1P
.RT
.ad b
.RT
.sp 1P
.LP
B.9.2
    \fIInterface point\fR
.sp 9p
.RT
.PP
One of at least two physical locations associated with an
interface. The interface points mark the end of the transmission medium
which supports the interface and may be the location of connectors (if
used).
.PP
The reach of any interface may be extended by the use of a
transmission system, providing that the transmission system is transparent
in regards to the functions transported by the interface. In such a case,
two
further interface points would be required. See Figure\ B\(hy5/G.960.
.RT
.LP
.rs
.sp 10P
.ad r
\fBFigure B\(hy5/G.960, p.\fR
.sp 1P
.RT
.ad b
.RT
.PP
B.9.3
A group of individual accesses may be multiplexed or
concentrated together to comprise a higher order access (i.e.\ V\d2\uor
\d6\ufor basic access higher order interfaces).
.PP
There is only one V reference point at which the V interfaces
may be implemented (between LT and ET). See Figure\ B\(hy6/G.960.
.PP
This approach aligns with the use of I\dB\uand I\dA\uinterface points in
Recommendations\ I.430 and I.431.
.RT
.LP
    \(em
    with the modelling technique used so far;
.LP
    \(em
    with the terminology used so far;
.LP
    \(em
    with the fact that an S or T reference point may support a
range of interfaces (Recommendations\ I.430/I.431);
.LP
    \(em
    does not contradict Recommendation Q.512.
.bp
.LP
.rs
.sp 20P
.ad r
\fBFigure B\(hy6/G.960, p.22\fR
.sp 1P
.RT
.ad b
.RT
.LP
.rs
.sp 29P
.LP
\fBMONTAGE:\ \fR REC. G.961 A LA FIN DE CETTE PAGE
.sp 1P
.RT
.LP
.bp