Collection of Internet/Collection of Internet.iso/faq/comp/isdn_faq

Text File | 1994-04-06 | 68KB | 1,709 lines

Newsgroups: comp.dcom.isdn,comp.answers,news.answers
Path: bloom-beacon.mit.edu!hookup!news.kei.com!sol.ctr.columbia.edu!hamblin.math.byu.edu!news.byu.edu!news.mtholyoke.edu!nic.umass.edu!noc.near.net!mv!fastball.unimaster.com!cherkus
From: [e-mail] (Dave Cherkus)
Subject: comp.dcom.isdn Frequently Asked Questions
Approved: [e-mail]
Keywords: ISDN FAQ telecom
Originator: [e-mail]
Distribution: world
Message-ID: <[e-mail]>
Nntp-Posting-Host: fastball.unimaster.com
Sender: [e-mail] (System Administrator)
Supersedes: <unknown>
Reply-To: [e-mail] (Dave Cherkus)
Expires: Thu, 11 Nov 1993 00:00:00 GMT
Summary: This posting contains a list of Frequently Asked
         Questions (and their answers) about ISDN.
Organization: UniMaster, Inc.
Date: Wed, 6 Apr 1994 11:56:51 GMT
Followup-To: comp.dcom.isdn
Lines: 1686
Xref: bloom-beacon.mit.edu comp.dcom.isdn:4120 comp.answers:4787 news.answers:17732

Archive-name: isdn-faq
Last-modified: $Date: 1994/04/06 06:59:45 $
Version: $Revision: 3.3 $

[Ed. Note:  I'm now using post_faq from Jonathan I. Kamens to post
 the faq every 14 days from cron.  There's lots of new material
 in this version that's been waiting on me to finish playing with
 the posting software... ]

-----
Frequently Asked Questions and Answers
comp.dcom.isdn

These questions and answers have (almost entirely) been extracted from
comp.dcom.isdn.  Please post any comments or new material that you
have, or email them to the current FAQ editor, [e-mail].
In particular, the vendor equipment chart is incomplete.  If you want
to share vendor equipment info, just cut and paste the headers from the
chart below and create a new entry for the new information, and send it
to me.

This FAQ consists almost entirely of information posted to this group.
There are a fair number of holes and there may be some outdated
information in it.  There is no claim of completeness or guarantee of
accuracy of any kind, or no warranties for merchantability or fitness
for a particular purpose.  If you have some useful information that you
would like to share, email it to me.  My goal is to have the FAQ mirror
the information provided to the newsgroup itself.  The next-to-last
section of this FAQ gives references that provide much more information
than this FAQ does.

I would like to thank Sean Welch for creating the previous edition
of the FAQ.  His work is still responsible for the majority of the
information gathered here.  I hope to continue the fine example that
Sean has set.

Questions with answers:

  1) What is ISDN?
  2) What does an ISDN network connection look like?
  3) What will Basic Rate (2B+D) ISDN look like in my house/office?
  4) Can the existing local loop lines be reused for ISDN?
  5) How does this compare to regular phone line services?
  6) Is caller ID available on ISDN?
  7) What do I get above and beyond plain old telephone service?
  8) What do ISDN phones cost?
  9) Can you use existing telephone equipment with the voice portion?
 10) What is National ISDN?
 11) What is the NIUF?
 12) What is ATM?
 13) What is B-ISDN?
 14) What is BONDING?
 15) Data Encapsulation for IP over ISDN
 16) Full Motion Video over ISDN
 17) How do I find out about getting ISDN in my area?
 18) Where can I find what all of these acronyms mean?
 19) What are the relevant standards?
 20) Who is shipping what?
 21) How about that SPARCstation 10?
 22) How about that IBM Waverunner?
 23) What is a SPID? How come my ISDN device won't work without one?
 24) Will an ISDN terminal equipment that works in one country
     work properly when it is installed in another country?
 25) Will ISDN terminal equipment that works with one vendor's ISDN
     switch work properly when it is used with another vendor's switch?
 26) Do different manufacturers Terminal Adaptors interoperate when used
     asynchronously?
 27) Why do I get only about 19.2k throughput from my TA?
 29) How long should call setup take when using a TA?
 29) Can I get on-line National ISDN information from Bellcore?
 30) Where can I read more?
 31) Who do I have to thank for this list?

Questions for which I have not yet put together an answer, but for which I
am accepting suggestions:

 a) What programming API's are useful for creating ISDN applications?
    (e.g. Sun, Microsoft TAPI, NIUF ASI, ETSI(?), CAPI(?), more(?))
    What are their strengths and weaknesses?

---

1)  What is ISDN?

ISDN stands for "Integrated Services Digital Networks", and it's a
CCITT term for a relatively new telecommunications service package.
ISDN is basically the telephone network turned all-digital end to end,
using existing switches and wiring (for the most part) upgraded so that
the basic "call" is a 64 kbps end-to-end channel, with bit-diddling as
needed (but not when not needed!).  Packet and maybe frame modes are
thrown in for good measure, too, in some places.  It's offered by local
telephone companies, but most readily in Australia, France, Japan, and
Singapore, with the UK and Germany somewhat behind, and USA
availability somewhat more behind.

[e-mail] (Winston Seah)
[e-mail] (Fred R. Goldstein)
[e-mail] (Paul Antoine)
---

2)  What does an ISDN network connection look like?

A Basic Rate Interface (BRI) is two 64K bearer ("B") channels and a single
delta ("D") channel.  The B channels are used for voice or data, and the D
channel is used for signaling and/or X.25 packet networking.  This is the
variety most likely to be found in residential service.

Equipment known as a Terminal Adapter (TA) can be used to adapt these
channels to existing terminal equipment standards such as RS-232 and
V.35.  This equipment is typically packaged in a similar fashion to
modems, either as standalone units or as interface cards that plug into
a computer or various kinds of commmunications equipment (such as
routers or PBXs).  TA's do not interoperate with the modem; it replaces
the modem.  Another common type of equipment can be used to implement a
bridge between local area networks using the ISDN channel to transport
the data.  Of course, more traditional devices such as telephones
and fax machines can be attached to the BRI, assuming they have the
proper interface hardware and software.

The BRI will require a device to perform the role of Network
Termination, or NT.  In the case where the TA is attached to a PBX
(defined below), the PBX will play the role of the NT.  In most
residential situations, a seperate standalone device will perform the
role of NT, or if there will be only one device attached to the BRI,
the one device can logically replace the NT device.  The major function
of the NT is to allow more than one device to have access to the 2 B
channels provided by the ISDN BRI.  For instance, you may have an ISN
telephone, an ISDN fax and an ISDN computer interface attached to the
BRI.  Each device can listen for calls and only connect to a B channel
when it identifies a message requesting a service it can provide.

The NT only implements part of the channel sharing scheme; the other
devices participate as well, and the communication protocol used by the
NT and the other devices is an integral part of the channel sharing
scheme.  The NT also performs other functions; it translates the bit
encoding scheme used on the lines between it and the telephone company
(the U loop) to the encoding used betyeen it and the devices.  These
schemes are different because the device to NT encoding was designed to
enable channel sharing whereas the NT to telco encoding was designed to
allow transmission across long distances.

In the United States, the customer pays for the NT device.  so don't
forget to include the cost of this unit in your cost estimates, or if
you don't need the multiple device attachment feature, try to find a
device that does not require the NT device (i.e. it provides the U
interface instead of the S/T interface; more on this in the next
section, and in the references).  If you are not in the United States
the telephone company provides the NT device, but remember there is no
such thing as a free lunch - you are probably paying for it through
increased rates, or increased taxes, etc. (flames to sci.economics or
alt.talk.politics).

Another flavor of ISDN is Primary Rate Interface (PRI). Inside North
America and Japan, this consists of 24 channels, usually divided into
23 B channels and 1 D channel, and runs over the same physical
interface as T1. Outside of these areas the PRI has 31 user channels,
usually divided into 30 B channels and 1 D channel and is based on the
E1 interface.  It is typically used for connections such as one between
a PBX (private branch exchange, a telephone echange operated by the
customer of a telephone company) and a CO (central office, of the
telephone company) or IXC (inter exchange carrier, a long distance
telephone company).

[e-mail] (Kevin Collins)
[e-mail] (Dave Evans)
[e-mail] (Andrew Scherpbier)
[e-mail] (Dave Cherkus)
[e-mail] (Oliver Jones)
[e-mail] (Gary C. Kessler)
----

3)  What will Basic Rate (2B+D) ISDN look like in my house/office?

[ Ed Note: this section was very inaccurate in the old FAQ!
  I've taken another swing at it - comments? ]

An ISDN BRI U-Loop is 2 conductors from the CO (telephone company
central office) to the customer premises.  Its maximum length may be
5.5 km (18000 ft).  At the customer premises the U-loop is terminated
by an NT1 (network termination 1) device, assuming that there is no PBX
(private branch exchange) between the ISDN terminal equipment and the
CO, which is the usual case for homes and most offices.  Note that in
ISDN terminology, "terminal" can mean any sort of end-user ISDN device,
such as data terminals, telephones, FAX machines, etc.

The NT1 drives a S/T-bus which is usually 4 wires.  It may be 6 or 8 in
some cases.  In these cases, the extra wires are used provide power to
operate telephones when normal power fails.  Outside North America
emergency mode operation supports basic voice service only in the case
of loss of local power. In emergency mode operation the NT1 receives up
to 1.2W from the central office. In North America there is no provision
for emergency mode operation.

The S/T bus is sometimes called the passive bus, because there are no
repeaters on the line between the NT1 and the devices.  It can be
implemented using the same cable and connectors as is 10 base T
Ethernet.  There may be up to 8 devices on the S/T bus.   The bus may
be formed with splitters and T connectors - it is a bus, not a star.
The D channel is used to control the attachment of the one to eight
devices to the two B channels.  No two devices attach to the same B
channel at the same time.

So, without a PBX, your house/office will look like:

                 S Bus                 U Loop    |
    +--------+ 4-8 wires +-------+    2-4 wires  |
    |Terminal|-----+-----|  NT1  |--------------[| wall (to telco CO)
    +--------+     |     +-------+               |
    +--------+     |                             |
    |Terminal|-----+
    +--------+     |
                   :
    +--------+     |
    |Terminal|-----+
    +--------+

With a PBX, the picture does not change much:

                 T Bus               S Bus              U Loop    |
    +--------+ 4-8 wires +-------+ 4-8 wires +-------+ 2-4 wires  |
    |Terminal|-----+-----|  NT2  |-----------|  NT1  |-----------[| wall
    +--------+     |     | (PBX) |           +-------+            |
    +--------+     |     +-------+                                |
    |Terminal|-----+
    +--------+     |
                   :
    +--------+     |
    |Terminal|-----+
    +--------+

Note that the S bus connects an NT1 to a terminal, whereas the T bus
connects a PBX (which is called a NT2) to a terminal, but we've been
using the name S/T bus up to this point.  Electrically, the S and T
busses are the same, which is why the name S/T bus is almost always
used.  This makes sense; the terminal should see the same physical
interface whether it is hooked up with or without a PBX.  But,
logically they are different.  The telephone company needs to know that
there is a PBX between itself and the user so that it can coordinate
its efforts with the PBX.  So, in cases where the difference is
important, the specifications use the S and T terminology.

When there is no PBX in the picture, the NT1 device is usually a
standalone device that is packaged a lot like a modem: in a small box
when there are only a few, and in a rackmount when you need a lot of
them.  In the United States, the customer buys the NT1 but in most of
the rest of the world the telephone company provides the NT1.  When
there is a PBX the rackmounted NT1s are quite common.

Unfortunately, the NT1 is not an inexpensive device.  It has to convert
between the signalling used on the U loop (which is operates over long
distances (5.5 km, 18000 ft) in a noisy environment and does not have
to deal with contention between devices) and the signalling of the S/T
bus (which operates over shorter distances in a quieter environment but
it does have to deal with contention between devices).

[e-mail] (Dave Cherkus)
[e-mail] (Cliff Frost)
[e-mail] (Curt Welch)
[e-mail] (Dror Kessler)
[e-mail] (Eric Boll)
[e-mail] (Greg Larson)
[e-mail] (Kevin J. Rowett)
[e-mail] (Paul Antoine)
[e-mail] ( Patton M. Turner)
[e-mail] (Ronnie B. Kon)
--

4) Can the existing local loop lines be reused for ISDN?

The ISDN pairs are the same wires as used for regular telephone
service.  If you became an ISDN user at home, the same wire pair that
now provides your telephone service would be used to provide ISDN
(assuming you no longer have the regular line).

Most of the lines do not require any special conditioning.  Yes, if
a line has load coils on it they must be removed, BUT load coils
are usually only found on existing lines that are 15,000 feet or
longer.  As to lines with bridge taps, the 2B1Q line transmission
scheme (not to be confused with 2B + D channelization) is tolerant
of a certain amount of bridge taps and, therefore it is only a minimal
subset of existing lines (lines with bridge taps whose total length is
greater than 3000 feet for the bridge taps) that would require
special "de-conditioning."

With those things as the criteria, (in North America) we find than
generally around 90% or so of existing telephone lines need no
"de-conditioning" in order to be used for ISDN BRI service.

[e-mail] (sohl,william h)
---

5) How does this compare to regular phone lines?

The ISDN line may act like two independent phone lines with two numbers.
Depending on the CO equipment, conferencing features etc. may be available
(conferencing in the telephone switch).  BRI ISDN phones can support key-set
features such as you would expect to get on an office PBX like:
     - multiple DNs / lines.
     - conferencing features.
     - forwarding features.
     - speed call.
     - call park.
     - call pickup.
     - ring again.

[e-mail] (Curt Welch)
[e-mail] (Greg Larson)
---

6)  Is caller ID available on ISDN?

Caller ID (name or number display) may be supported (depending on the
CO setup). The availability of caller ID for residential phones would
depend on the capabilities of the local phone network and legislation
allowing or disallowing caller ID.  The availability of Caller ID
relies on the underlying switching protocol used by the switches
that make up the telephone system (e.g. SS7).

[e-mail] (Curt Welch)
[e-mail] (Greg Larson)
[e-mail] (Gary C. Kessler)
---

7)  What do I get above and beyond plain old telephone service?

Plain old telephone service is transmitted between the central office
to your home or office telephone set (or modem, or fax) in analog
form.  At the central office, the analog signal is converted to a
series of digital samples at a rate of 8000 samples per second.  Each
sample is seven or eight bits in length.  As the signals for a
telephone call move around the central office, or between central
offices, they are transmitted in digital form.  Thus, a telephone call
consumes a transmission bandwidth of either 56 or 64 kilobits per
second.  The theoretical (Nyquist) limit for the frequency response of
a signal sampled 8000 times per second is 4kHz.  However, due to
various losses in the telephone system, the frequency response of an
ordinary telephone call is usually quoted as 3.1kHz.  Ordinary
modem-based data transmission uses schemes for encoding data in an
analog signal so it fits in this 3.1kHz bandwidth.  14.4kbps is a
commonly available transmission rate at the high end of the scale.
With this transmission rate, over three-quarters of the bitrate handled
by the central office is wasted.

Notice that in telephony, 64kpbs means 64000 bits per second, whereas
in computer engineering 64k bytes typically means 65536 bytes.

ISDN brings the digital signal all the way to your home or desktop.  With
ISDN, you can place a data call which uses all 56kbps or 64kbps, because
there is no need to convert the signal to analog in your modem and back
to digital at the central office.  The availability of the full bandwidth
presents some interesting technological opportunities:
   -- transmission of high-fidelity compressed audio
   -- transmission of encrypted audio
   -- transmission of lots of data
   -- transmission of other compressed signals, such as video

Basic-rate ISDN (BRI) offers two channels of this service.  In BRI, the
connection between your site and the central office offers 64kbps
bidirectionally on each channel.  Each of these channels may be used
for a voice call, for circuit-switched data, or for X.25 packet
switched data.  Thus, the existing POTS circuit can be conditioned to
carry two calls at the same time.  (Your mileage may vary;  you have to
specifically order and pay for the various services from your telephone
company, just as you have to order and pay for Call Waiting for an
ordinary phone line.  Also, not all services are available everywhere;
X.25 connectivity between COs is a notable problem in the Greater
Boston area as of 9/93, for example.)

Incidentally, ISDN brings another interesting service to your home or
desktop:  a highly reliable 8000Hz clock signal.  In most cases, the
central office switches, long-distance carriers, and ISDN terminal
equipment all operate with exactly the same clock frequency.  In a
real-time communications environment (like a voice phone call) this
means that there's no need to compensate for differences between the
sampling rates at each end of the call.

One of the other features it that instead of the CO sending an AC ring
signal to activate your bell, it sends a digital package that tells WHO
is calling (if available), WHAT TYPE of call (speech, datacomm?), the
NUMBER DIALED (maybe one of your aliases) and some other stuff. Your
equipment can then analyze this stuff and make an "intelligent" decision
what to do with it. For example, a phone (with speech-only capacity)
would completely ignore a datacomm call while a Terminal Adapter (ISDN
"modem") or a phone with built-in datacom functions would respond to it.
If you have several "aliases" tied to your line, you can program certain
phones to answer calls for certain numbers only.  Datacomm calls contain
baud rate and protocol information within the setup signal so that the
connection is virtually instantaneous (no messing around with trying
different carriers until both ends match).

[e-mail] (Curt Welch)
[e-mail] (Torsten Lif)
[e-mail] (Oliver Jones)
[e-mail] (Helge Oldach)
---

8)  What do ISDN phones cost?

The ISDN sets can cost between $180 for an AT&T 8503T ISDN phone from
Pacific Bell up to $1900 depending on what/how many features are needed.

A recent report states that the price is $536.90 for an AT&T 7506 with
the RS-232 port on the back and $102.70 to get the 507A adaptor to hook
analog devices to my 7506.

Recent quotes were "$200" for a Coretelco 1800 and "$600" for a Fujitsu
SRS 1050.

[e-mail] (Dave Evans)
[e-mail] (Brad Huntting)
[e-mail] (Joe Ilacqua)
[e-mail] (Scott Turner)
---

9)  Can you use existing telephone equipment with the voice portion?

Terminal Adapters (TA'a) are available that will interface non ISDN terminal
equipment (TE), called TE2 to the S/T interface.  At least one RBOC provides
a modem pool to allow for interchange of data with POTS subscribers.  Bellcore
may approve a standard to allow a analog pair to interface to POTS sets from
a NT1.  Also w/o a NT2 only one set can be connected to a B channel at a time.  This prevents 2 sets from participating in the same voice call.

[e-mail] ( Patton M. Turner)
[e-mail] (Joe Ilacqua)
---

10) What is National ISDN?

Because of the breadth of the international ISDN standards, there are a
number of implementation choices that vendors of ISDN equipment can
make.  Given the number of choices vendors can make, different vendors
equipment may not interoperate.  In the United States, Bellcore has
released a series of specifications to try to avoid these
interoperability problems.  These are the National ISDN
specifications.  Contact the Bellcore ISDN hot line listed below for
more information.

[e-mail] (Gary C. Kessler)
[e-mail] (Dave Cherkus)
----

11) What is the NIUF?

North American ISDN Users Forum (NIUF) is an org. of ISDN-interested
parties, coordinated by NIST (National Institute of Stds. and Tech.)
Contact:

    NIUF Secretariat
    National Institute of Standards and Technology
    Building 223, Room B364
    Gaithersberg, MD  20899
    [phone] voice
    [phone] fax
    [phone] BBS  8N1  2400 bps

Bellcore has made the PostScript files for "A Catalog of National
ISDN Solutions for Selected NIUF Applications, Second Edition"
accessable via anonymous ftp from the machine info.bellcore.com.
This document has a tremendous amount of information about
ISDN products and vendors, among many other things.  See the item
below for details.

[e-mail] (Dave Cherkus)
----

12) What is ATM?

ATM (Asynchronous Transfer Mode) is a switching/transmission technique
where data is transmitted in small, fixed sized cells (5 byte header,
48 byte payload).  The cells lend themselves both to the time-division-
multiplexing characteristics of the transmission media, and the packet
switching characteristics desired of data networks.  At each switching
node, the ATM header identifies a "virtual path" or "virtual circuit"
that the cell contains data for, enabling the switch to forward the
cell to the correct next-hop trunk.  The "virtual path" is set up
through the involved switches when two endpoints wish to communicate.
This type of switching can be implemented in hardware, almost essential
when trunk speed range from 45Mb/s to 1Gb/s.

One use of ATM is to serve as the core technology for a new set of ISDN
offerings known as Broadband ISDN (B-ISDN).

For more information, read comp.dcom.cell-relay.

This group has a Frequently Asked Questions list;  it is posted
to news.answers and is in various archives as cell-relay-faq.

[e-mail] (Art Berggreen)
[e-mail] (Dave Cherkus)
--------

13) What is B-ISDN?

Broadband ISDN refers to services that require channel rates greater than
a single primary rate channel.  While this does not specificially imply
any particular technology, ATM will be used as the switching infrastructure
for B-ISDN services.

B-ISDN services are categorized as:

    INTERACTIVE
     Conversational -- such as videotelephony, videoconferencing, ...
     Messaging -- such as electronic mail for images, video, graphics,...
     Retrieval -- such as teleshopping, news retrieval, remote education,...

    DISTRIBUTION
     Without user presentation control -- electronic newspaper, electronic
         newspaper, TV distribution
     With user presentation control -- remote education, teleadvertising,
         news retrieval

More information: ITU TSS Rec. I.211.

[e-mail] (Gary C. Kessler)
--------

14) What is BONDING?

An inverse multiplexing method of the Bandwidth ON Demand
INteroperability Group, implemented by most (all?) inverse multiplexor
vendors to interoperate with inverse multiplexors of other vendors.

BONDING is a set of protocols developed by U.S. inverse multiplexor
that supports communication over a set of separate channels as if their
bandwidth were combined into a single coherent channel.  For example it
supports a single 384 kb/s data stream over 6 64 kb/s channels.

The specification defines a way of calculating relative delay between
multiple network channels and ordering data such that what goes in one
end comes out the other.

Most (all?) vendors also have their own proprietary methods that
usually add features functions not present in BONDING mode 1.  Mode 1
is the mode used for recent interoperability testing between vendors.

Chip Sharp at Teleos has made available electronic copies of the
BONDING (Bandwidth on Demand Interoperability Group) 1.0 and 1.1
specifications.  The specs are available via WWW, gopher, anonymous
FTP, DECnet COPY, and AFS (see instructions below).

The following files are available:

- aaareadme-networks       help file (in ascii text)
- bdmain.doc               main body of BONDING 1.0 specification
                           (Word for Windows 2.0 format)
- bdmain.ps                main body of BONDING 1.0 specification (Postscript)
- bdannex.doc              annex of BONDING 1.0 specification (Word
                           for Windows 2.0 format)
- bdannex.ps               annex of BONDING 1.0 specification (Postscript)
- bd_v1_1.doc              changes for BONDING 1.1 specification (Word
                           for Windows 2.0 format)
- bd_v1_1.ps               changes for BONDING 1.1 specification (Postscript)

Transfer Instructions:

WWW:
    server: www.hep.net
    URL: gopher://www.hep.net:70/11/info_center/networks/bonding

Gopher:
    server: gopher.hep.net
    Bookmark:
    Name=Bandwidth on Demand Interoperability Group (BONDING) Documents
    Type=1
    Port=70
    Path=1/info_center/networks/bonding
    Host=gopher.hep.net

Anonymous FTP:
    server: ftp.hep.net
    directory: networks/bonding

DECnet COPY (only for those on HEP-NSI DECnet):
    HEPNET::[ANON_FTP.NETWORKS.BONDING]

AFS:
    /afs/hepafs1.hep.net/public/anon_ftp/networks/bonding

[e-mail] (Marco S Hyman)
"Bob Larribeau" <[e-mail]>
"David E. Martin" <[e-mail]>
---

15) Data Encapsulation for IP over ISDN

A decision was made at the Amsterdam IETF to state that all systems
wishing to guarantee IP interoperability should implement PPP.  Such
systems may also implement the Frame Relay or X.25 encapsulations, and
an RFC will be published delineating how, when it is known that the
encapsulations are limited to that set of three, they may be
distinguished by examination of the first correctly checksumed and HDLC
bit-stuffed packet.

There is an Internet Draft from the Point-to-Point Protocol Working
Group of the Internet Engineering Task Force that describes the use of
PPP over ISDN.  This draft is named draft-ietf-pppext-isdn-NN.txt
in the internet-drafts Shadow Directories on nic.ddn.mil,
nnsc.nsf.net, nic.nordu.net, ftp.nisc.sri.com, munnari.oz.au,
Germany.EU.net and on many, many other mirror archives.

This is also discussed in RFC 1356 by Malis, et. al.

[e-mail] (Keith Sklower)
[e-mail] (Dave Cherkus)
[e-mail] (Gary C. Kessler)
--------

16) Full Motion Video over ISDN

In ISDN, video isn't a "service being offered" - at least not for
low/midrange quality. You buy the proper equipment for both
subscribers, plug it in, and place the call. Just like speaking French
on ISDN isn't something being offered - it is something you just do,
yourself.

Video telephony over narrowband ISDN is governed by a suite of TSS
(formerly CCITT) interoperability standards.  The overall video
telephony suite is known informally as p * 64, and formally as standard
H.320.   H.320 is an "umbrella" standard;  it specifies H.261 for video
compression, H.221, H.230, and H.242 for communications, control, and
indication, G.711, G.722, and G.728 for audio signals, and several
others for specialized purposes.  A common misconception, exploited by
some equipment manufacturers, is that compliance with H.261 (the video
compression standard) is enough to guarantee interoperability.

Bandwidth can be divided up among video, voice, and data in a
bewildering variety of ways.  Typically, 56kbps might be allocated to
voice, with 1.6kbps to signalling (control and indication signals) and
the balance allocated to video.

An H.320-compatible terminal can support audio and video in one B
channel using G.728 audio at 16 kb/s.  For a 64 kb/s channel, this
leaves 46.4 kb/s for video (after subtracting 1.6 kb/s for H.221
framing).

The resolution of a H.261 video image is either 352x288 (known as CIF)
or 176x144 (known as quarter-CIF or QCIF).  The frame rate can be
anything from 30 frames/second and down.  Configurations typically use
a 2B (BRI) or a 6B (switched-384 or 3xBRI with an inverse multiplexer)
service, depending on the desired cost and video quality. In a 384kbps
call, a video conferencing system can achieve 30 frames/second at CIF,
and looks comparable to a VHS videotape picture. In a 2B BRI call, a
standard video phone can achieve 15 frames/second at CIF.

Those who have seen the 1B video call in operation generally agree that
the quality is not sufficient for anything useful like computer based
training - only for the social aspect of being able to *see* Grandma as
well as hear her (sort of like the snapshot pictures you make with that
$5 camera with no controls).

A 2B picture, on the other hand, is for all practical purposes
sufficient for remote education, presentations etc. Rapidly changing
scenes are still not very well handled, but as soon as the picture
calms down, the sharpness and color quality are impressive (considering
that only two plain phone channels are being used). With 2B+D being the
standard BRI, this kind of picturephone will be usable "everywhere"
(including private homes).

However, it should still be noted that 6xB or H0 does allow for dramatic
improvement in picture quality compared to 2xB.  In particular, H.320
video/audio applications will often allocate 56kbps for audio, leaving
only 68.8kbps for video when using 2xB.  On the other hand, using H0
would get you 326.4kbps for video with 56kbps for audio. Alternative
audio algorithms can improve picture quality over 2xB by not stealing
as many bits.  Note that 6B is not identical to H0; the latter is a
single channel which will give you 80kbps above that of six separate B
channels.  Inverse multiplexors can be used to combine B channels.

[e-mail] (Ketil Albertsen,TIH)
[e-mail] (Kevin Davis)
[e-mail] (Oliver Jones)
[e-mail] (Mike Souryal)
---

17) How do I find out about getting ISDN in my area?

[Ed. Note:  I would appreciate anyone adding info for this section.
 I would hope that the info would be for an ISDN specific operation,
 not a generic telephone company office]

  Australia:
    Telecom:  008 077 222 (voice), [phone] (fax)

  Germany:
    Deutsche Bundespost Telekom

    IfN - Ingenierubuero fuer Nachrichtentechnik
    Haidelmoosweg 52
    D - 78467 Konstanz
    Tel: [phone]
    FAX: [phone]

  North America:
    North American ISDN Users Forum (NIUF): see item above

  United Kingdom:
    British Telecom ISDN Helpdesk
    0800 181514 from within the UK,
    [phone] from outside.

    Mercury Data Communication
    0500 424194 from within the UK,
    [phone] from outside.

  United States:
    I suggest that you call the local telephone service center office
    and ask for the name and number of the Marketing Product Manager
    for ISDN services.  If the service rep cannot make heads or tails
    of your question, ask to speak to the local service center manager
    for complex business services.  This person should be able to
    direct you to the right place.  For the Bell companies, this
    position is normally part of the telephone company's core marketing
    staff at their headquarters location.

    Bellcore national ISDN information clearing house hotline:
    800 992-4736

    Bellcore's "ISDN Deployment Data", Special Report (SR) 2102.

    Bellcore document ordering: US: 1-800-521-2673, other: 1-908-699-5800

    Bell Atlantic: 800-570-ISDN

    Ameritech: 800-8326-328

    You can call Pacific Bell at [800] 995-0346.  This is an extensive
    menu-driven system (yuck) that allows Pac Bell customers to enter their
    area code and prefix to find out what services are available.  It
    doesn't tell you which switch, though.  Pac Bell also operates a
    Gopher server at gopher.pacbell.com or gw.pacbell.com.

    GTE also has a menu-driven information service at [800] 4GTE-SW5.

    NYNEX: 1-800-438-4736, 800-GET-ISDN, 800-698-0817 or 212-626-7297.

    Combinet "BBS":

      By popular demand, the Combinet "BBS" providing information on ISDN
      availability in many areas of the US is now available via the Internet.
      The information is supplied by Bell Communications Research and various
      Operating Companies and is updated periodically as new information
      becomes available.

      To access the service, telnet to bbs.combinet.com and login as
      isdn (no password is required).  After entering an area code and
      three-digit prefix, the service displays the availability of ISDN.
      Also displayed is information about carrier installation prices and
      monthly charges.

      For those without direct Internet access, the service continues to be
      available on a dialup basis using a 2400 bit/sec modem at [phone].


[e-mail] (Ben Harrell)
[e-mail] (Eric A. Litman)
[e-mail] (Marc Evans)
[e-mail] (Al Varney)
[e-mail] (Gerhard Bernot)
[e-mail] (Jamie Honan)
[e-mail] (David L. Markowitz)
Peter Ilieve <[e-mail]>
[e-mail] (Gerald L. Hopkins)
[e-mail] (Gary C. Kessler)
[e-mail] (Jim Fenton)
[e-mail] (James - The Keeper)
---

18)  Where can I find what all of these acronyms mean?

An archive of telecommunication related files are maintained on
lcs.mit.edu in the telecom-archives sub directory.  There is a
glossary of general telecom acronyms, as well as an ISDN specific
list.

[e-mail] (Joe Smith) asks:
[e-mail] (Peter M. Weiss)
----

19) What are the relevant standards?

There are numerous CCITT standards on ISDN.  References in the book
bibliography (especially Stallings and appendix B of Kessler) contain
more details.

Q.921
(aka I.441) "ISDN User-Network Interface Data Link Layer Specifications", 1988
             The D channel protocol. Found in Blue book Fascicle VI.10

Q.931
(aka I.451) "ISDN User-Network Interface Layer 3 Specification for Call control"
            1988. The messages that are sent over the D channel to set up
            calls, disconnect calls etc. Found in Blue book Fascicle VI.11
    Q.930: General Overview
    Q.931: Basic ISDN call control
    Q.932: Generic procedures for the control of ISDN supplementary services
    Q.933: Frame Mode Call Control
    Q.2931 (ex-Q.93B): B-ISDN Call control

G.711: Pulse Code Modulation (PCM) of Voice Frequencies

G.722: 7-kHz Audio Coding Within 64 kbit/s

G.728: Coding of Speech at 16 kbit/s Using Low-Delay Code Excited
       Linear Prediction (LD-CELP)

H.320: Narrow-band Visual Telephone Systems and Terminal Equipment

H.221: Frame Structure for a 64 to 1920 kbit/s Channel in Audiovisual
       Teleservices

H.230: Frame Synchronous Control and Indication Signals for Audiovisual Systems

H.242: System for Establishing Communications Between Audiovisual Terminals
       Using Digital Channels up to 2 Mbit/s

H.261: Video Codec for Audiovisual Services at p x 64 kbits/s

H.243: Basic MCU Procedures for Establishing Communications Between Three or
       More Audiovisual Terminals Using Digital Channels Up to 2 Mbit/s

I.2xy      "ISDN Frame Mode Bearer Services", 1990

I.310      ISDN - Network Functional Principles
I.320      ISDN protocol reference model
I.324      ISDN Network Architecture
I.325      Reference configs for ISDN connection types
I.326
I.330      ISDN numbering and addressing principles
I.331      Numbering plan for ISDN (and several more in I.33x relating
           to numbering and addressing and routing)
I.340      ISDN connection types
I.350/351/352    refer to performance objectives
I.410-412   refer to user-network interfaces
           as do I.420 and 421
I.430/430  Layer 1 specs
I.440/441  Layer 2 specs (Q.921)
I.450-452  Layer 3 specs (Q.931)
    I.450: General Overview
    I.451: Basic ISDN call control
    I.452: Extensions
I.460-465  Multiplexing and rate adaption
I.470      Relationship of terminal functions to ISDN

V.110
(aka I.463) "Support of DTE's with V Series Type Interfaces by an ISDN"
            Terminal rate adaption by bit stuffing.  C.f. V120.

V.120
(aka I465) "Support by an ISDN of Data Terminal Equipment with V series
            Type Interfaces with Provision for Statistical Multiplexing" 1990
            (This has been amended since the blue book). An alternative to
            V.110

V.25bis    calling mechanism under synchronous.

CCITT standards can be obtained via:

    On line (anonymous ftp):
    [ Ed Note: I haven't had luck with these - comments? ]

    kum.kaist.ac.kr: /doc/STANDARDS/ccitt
    src.doc.ic.ac.uk/pub/computing/ccitt/ccitt-standards/ccitt

    Hard Copy:

    International Telecommunication Union
    Information Services Department
    Place des Nations
    1211 Geneva 20
    Switzerland

    TEL: [phone]
    FAX: [phone]
    Internet email: [e-mail]
    X.400 email: S=helpdesk;A=arcom;P=itu;C=ch

[e-mail]
[e-mail]
[e-mail]
[e-mail] (Gary C. Kessler)
---

20)  Who is shipping what?

  ISDN Products by Vendor:

    +------------------+--------------------------------------------+
    |                  |            Product Type                    |
    |  Vendor          +----+----+----+----+----+----+----+----+----+
    |                  | IF | TA | BR | RO | TE | IC | TS | VC | CC |
    +------------------+----+----+----+----+----+----+----+----+----+
    | AMD              |    |    |    |    |    |  x |    |    |    |
    | AT&T             |  x |  x |    |    |  x |  x |  x |    |    |
    | ANDO             |    |    |    |    |    |    |  x |    |    |
    | Ascend           |    |    |    |  x |    |    |    |    |    |
    | AT&T Microelect. |    |    |    |    |    |  x |    |    |    |
    | Combinet         |    |    |  x |    |    |    |    |    |    |
    | CPV-Stollmann    |  x |  x |  x |  x |    |    |    |    |    |
    | DGM&S            |    |    |    |    |    |    |    |    |  x |
    | diehl isdn       |  x |    |  x |    |    |    |    |    |    |
    | DigiBoard        |    |    |  x |    |    |    |    |    |    |
    | Digital Eq.      |  x |    |    |  x |    |    |    |    |    |
    | Gandalf          |  x |  x |    |    |    |    |    |    |    |
    | Hayes            |  x |  x |    |    |    |    |    |    |    |
    | IBM              |  x |    |    |    |    |    |    |    |    |
    | ISDN Systems     |  x |    |    |    |    |    |    |    |    |
    | Motorola UDS     |    |  x |    |    |    |    |    |    |    |
    | MITEL            |    |    |    |    |    |    |  x |    |    |
    | netCS            |  x |    |    |  x |    |    |    |    |    |
    | Network Express  |    |    |  x |  x |    |    |    |    |    |
    | Paxdata          |    |  x |  x |    |    |    |    |    |    |
    | Siemens          |    |    |    |    |    |  x |    |    |    |
    | Spider Systems   |    |    |    |  x |    |    |    |    |    |
    | Sun Microsystems |  x |    |    |    |    |    |    |    |    |
    | Telenetworks     |    |    |    |    |    |    |    |    |  x |
    | Teleos           |    |    |    |    |    |    |  x |    |    |
    | Telesoft         |    |    |    |    |    |    |  x |    |  x |
    | Telrad Telecomm. |    |    |    |    |    |    |  x |    |    |
    | Trillium         |    |    |    |    |    |    |    |    |  x |
    | Zydacron         |    |    |    |    |    |    |    |  x |    |
    +------------------+----+----+----+----+----+----+----+----+----+

      Key:

        IF: Interface Card
        TA: Terminal Adapter (Standalone)
        BR: Bridge
        RO: Router
        TE: Telephones
        IC: Integrated Circuit
        TS: Test Equipment
        VC: Video Teleconferencing Equipment
        CC: Call Control Software

Vendor Info:

Advanced Micro Devices
901 Thomson place
Mailstop 126
Sunnyvale, CA 94086
[phone] (voice)

American Telephone and Telegraph
1-800-222-PART: Quick access to small quanity orders of ISDN products.
Personal Desktop Video or TeleMedia Connection System:
    Visual Communications Products
    8100 East Maplewood Avenue 1st Floor
    Englewood, CO  80111
    [phone]  (800)VIDEO-GO  Prompt 3

ANDO:
7617 Standish Place
Rockville, MD 20855
voice: [phone]
fax:   [phone]
email:  [e-mail]

Ascend Communications, Inc.
1275 Harbor Bay Pkwy
Alameda, CA 94501
[phone]
[e-mail]

AT&T Microelectronics
Allentown, PA
[phone]
Distributer: CoSystems at 408.748.2190
  mktg: Steve Martinez at 408.748.2194 ([e-mail])
  tech: Gary Martin at 408.748.2195 ([e-mail])

Combinet
333 West El Camino Real, Suite 240
Sunnyvale, California 94087
[phone] (voice)
[phone] (fax)

CPV-Stollmann Vertriebs GmbH
Gasstrasse 18     P.O. Box 50 14 03
D-22761 Hamburg   D-22714 Hamburg
Germany           Germany
Phone: [phone]
Fax: [phone]
Electronic Mail:
        [e-mail] (general inquiries)
        [e-mail] (IPX router technical contact)
        [e-mail] (IP router technical contact)

DGM&S
609.866.1212

diehl isdn GmbH
Bahnhofstrasse 63
D-7250 Leonberg
Germany
Tel. [phone]
Fax. [phone]
email: [e-mail]

DigiBoard
6400 Flying Cloud Drive
Eden Prarie, MN 55344
[phone]  (voice)
[phone]  (fax)
[e-mail] (email)

Digital Equipment Co
REO2 G/H2
DEC Park
Worton Grange
Reading
Berkshire
England

Gandalf
Cherry Hill Industrial Center
Building 9
Cherry Hill, NJ 08002
(800) GANDALF (voice)

Hayes ISDN Technologies
501 Second St., Suite 300
San Francisco  CA  94107
[phone] (voice)
[phone] (fax)
ISDN Product Manager: Chris Brock ([e-mail])

International Business Machines
[phone]

ISDN Systems Corp.
Vienna VA USA
703-883-0933

MITEL Corporation
360 Legget Drive
Kanata, Ontario, Canada
K2K 1X3
Paul Mannone or Peter Merriman
[phone]

Motorola UDS
5000 Bradford Drive
Huntsville, AL 35805
[phone] (voice)

netCS Informationstechnik GmbH
Feuerbachstr. 47-49
12163 Berlin 41
Germany
Tele: +49.30/856 999-0
FAX: [phone]
E-Mail: [e-mail] / [e-mail]

Network Express
Andrew Hasley           Jim Hietala (West Region)  Randy Sisto (East Region)
VP, Sales               [e-mail]         [e-mail]
4251 Plymouth Road      342 Lester Ct.             11566 Ivy Bush Court
Ann Arbor, MI 48105     Santa Clara, CA 95051      Reston, Virginia 22091
[phone] (voice)  Tel. [phone]          Phone: [phone]
[phone] (fax)    Fax. [phone]          Fax:   [phone]

Paxdata Networks Limited
Communications House
Frogmore Road
Hemel Hempstead
HERTS HP3 9RW
UK
0442 236336 (voice)
0442 236343 (fax)
mktg: Jim Fitzpatrick ([e-mail])
tech: Giles Heron ([e-mail])

Siemens Components Inc.
Integrated Circuit Division
2191 Laurelwood Road
Santa Clara, CA 95054-1514
[phone]

Spider Systems
UK                         France                   Germany
Spider Systems Limited     Spider Systems SA        Spider Systems Limited
Spider House               Les Algorithmes          Schadowstrasse 52
Peach Street               Saint Aubin 91194        D-4000 Dusseldorf 1
Wokingham                  Gif-sur-Yvette           Germany
England                    Paris Cedex
RG11 1XH                   France
0734 771055 (voice)        (1) 69 41 11 36 (voice)  (0211) 93 50 120 (voice)
0734 771214 (fax)          (1) 69 41 12 27 (voice)  (0211) 93 50 150 (fax)

Sun Microsystems Computer Company (SMCC)
Mountain View, CA
(800) USA-4SUN

Telenetworks
Lauren May
Tel: [phone]
Fax: [phone]
[e-mail]

Teleos
2 Meridian Road
Eatontown, NJ 07724
908.389.5700

Telesoft
Chris Cox
512.282.6701

Telrad Telecommunications, Inc.
135 Crossways Park Drive
Woodbury, New York 11797
[phone]
1 800 645-1350

Trillium
310.479.0500

Zydacron, Inc.
670 Commercial Street
Manchester, NH 03101
Tel: [phone]
Fax: [phone]

Many of the references, including Kessler, provide information on ISDN
equipment.

[e-mail] (TONY KENOW)
[e-mail] (Gary Martin)
[e-mail] (Bob Clemmons)
[e-mail] (Marco S Hyman)
[e-mail] (David L. Markowitz)
[e-mail] (James J Allen [phone])
[e-mail] (Giles Heron)
---

21)  How about that SPARCstation 10?

The hardware on the SS10 supports 2 B channels (64K+64K) and 1 D
channel (16K) for a grand total 144K in marketing speak.  Typically you
might use both B channels for data, 1 channel for voice and 1 channel
for data, or 1 channel for data to 1 point and 1 channel for data to
another point.  In some parts of the world it's also popular to run
X.25 over the D channel.

Info from the SPARCstation 10 full announcement e-mail:

  - What Becomes Available When:
        o ISDN
            Chip on the motherboard                     (done)
            ISDN Drivers on Solaris 2.1 or greater      (done)
            Teleservices API                            Q1 CY93 Solaris 2.x
            Wide Area Networking software               Q1 CY93 Solaris 2.x
            The chip on the motherboard provides a BRI (basic rate interface)
            ISDN connection that is integrated with workstation audio.
            The drivers provide a low level interface to the hardware.
            The Teleservices API enables application development for
            workstation/telephony integration - providing functions like
            call setup, transfer, hold, confer, etc.  The API is hardware
            independent so that it will work with third party non-ISDN
            telephony hardware and software.  The WAN software enables
            data communication - running IP over ISDN (in other words,
            applications that run over ethernet will run over ISDN).
            In the first release, Sun will support data communications
            in the US (for the AT&T 5ESS switch), the UK, France, Germany
            and Japan.  We will support voice services in the US (for
            the AT&T 5ESS switch) only.

This is also now available on the SPARCstation LX, and available as an
SBus card for any SBus workstation running Solaris 2.1 or later.

The current set of ISDN drivers for Solaris 2.1 or greater support
the AT&T 5ESS switch;  the next release is expected to support
DMS-100 and national standard.

Get API_xtel* from sunsite.unc.edu:/pub/sun-info/white-papers for
more information on the API itself.  The XTel libraries, etc., are
not bundled with either Solaris 2.x or SunLink ISDN at this time.

SunLink ISDN description (quoted from Fall/Winter '93 SunExpress catalog):
The SunLink ISDN software included in both kits is based on the international
CCITT standard, and supports the following carrier-dependent implementations:
o  AT&T 5ESS (U.S.)
o  France Telecom VN2 (France)
o  DBT 1TR6 (Germany)
o  Britsh Telecom ISDN2 (U.K.)
o  NTT INS-Net 64 (Japan)

Sunlink ISDN software provides the following features:
o  Transparent IP connectivity, to allow you to run most existing IP
   applications, without modification, over ISDN
o  Graphics User Interface (GUI)-based configuration tool, for easy
   installation and administration
o  Security features, including callback, calling address, and PPP
   authentication password
o  Inactivity timer, for transparent open/close connections
o  Integrated network management with SunNetManager agent

[e-mail] (Dan Kegel)
[e-mail] (Tom Kessler)
[e-mail]
[e-mail] (David L. Markowitz)
---

22) How about that IBM Waverunner?

The IBM WaveRunner Digital Modem is an internal adapter for personal
computers (ISA or Microchannel) which can communicate over an ISDN
line to either ISDN destinations or analog modems and FAX machines.
WaveRunner requires ISDN Basic Rate service, an NT-1, and either
OS/2 2.1 or higher or Microsoft Windows 3.1 or higher.

WaveRunner uses AT-style commands, can be used with existing
communication application, supports V.120 encapsulation and performs
TCP/IP SLIP to Synchronous TCP/IP Translation.

The WaveRunner Hot Line at 1-919-254-ISDN is available for questions
Technical Support.

A complete description is available via anonymous ftp:

    ibminet.awdpa.ibm.com: pub/announcements/193-305

[e-mail] (Rob Jordan)
[e-mail] (Laurence V. Marks)
---

23) What is a SPID? How come my ISDN device won't work without one?

SPIDs are Service Profiles IDs.  SPIDs are used to identify what sort
of services and features the switch provides to the ISDN device.
Currently they are used only for SAPI 0 (circuit-switched) service.
They are used by "Fully Initializing" terminals which are specified by
the North American National ISDN standards, and perhaps others.

When a new subscriber is added, the telco personnel allocate a SPID
just as they allocate a directory number.  In many cases, the SPID
number is identical to the (full ten digit) directory number.  In other
cases it may be the directory number concatinated with various other
strings of digits, such as digits 0100 or 0010,  1 or 2 (indicating the
first or second B channel on a non-centrex line), or 100 or 200 (same
idea but on a centrex line) or some other, seemingly arbitrary string.
Some people report SPIDs of the form 01nnnnnnn0 for  AT&T custom and
01nnnnnnn011 for NI-1, where n is the seven digit directory number.
It is all quite implementation dependent.

When the subscriber plugs in a properly configured device to the line,
Layer 2 initialization (TEI assignment) takes place, establishing the
transport mechanism.  However if the subscriber has not configured the
given SPID into their ISDN device, the device should not perform layer
2 initialization and the subscriber will not be able to make calls.
This is, unfortunately, how many subscribers discover they need a
SPID.

Once the SPID is configured, the terminals go through an
initialization/identification state which has the terminal send the
SPID to the network in a Layer 3 INFOrmation message whereby the
network responds with an INFO message with the EID information element
(ie). Thereafter the SPID is not sent again to the switch. The switch
may send the EID or the Called Party Number (CdPN) in the SETUP message
to the terminal for the purpose of terminal selection.

SPIDs should not be confused with TEIs (terminal endpoint identifiers).
TEIs identify the terminal at Layer 2 for a particular interface
(line).  TEIs will be unique on an interface, whereas SPIDs will be
unique on the whole switch and tend to be derived from the primary
directory number of the subscriber.  Although they are used at
different layers, they have a 1-to-1 correspondence so mixing them up
isn't too dangerous. TEIs are dynamic (different each time the terminal
is plugged into the switch) but SPIDS are not. Following the
initialization sequence mentioned above the 1-to-1 correspondence is
established.  TEIs are usually not visible to the ISDN user so they are
not as well known as SPIDs.

The "address" of the layer 3 message is usually considered to be the
Call Reference Value (also dynamic but this time on a per call basis)
as opposed to the SPID, so the management entity in the ISDN device's
software must associate EID/CdPN on a particular TEI and Call Reference
Number to a SPID.

There are some standards that call for a default Service Profile, where
a terminal doesn't need to provide a SPID to become active.  Without
the SPID however, the switch has no way of knowing which terminal is
which on the interface so for multiple terminals an incoming call would
be offered to the first terminal that responded, rather than to a
specific terminal.

[e-mail] (winston (w.l.) sorfleet)
[e-mail] (Chuck Storry)
---

24)  Will ISDN terminal equipment that works in one country
     work properly when it is installed in another country?

There are three major problem areas.

The first has to do with voice encoding, and is only a problem if the
equipment is a telephone.  Equipment designed for use in North America
and Japan uses mu-law encoding when converting from analog to digital,
whereas the rest of the world uses A-law.  If the equipment can be
switched, then there will not be a problem with the voice encoding.

The second has to do with the way the equipment communicates with the
telephone exchange.  There are interoperability problems because there
are so many different services (and related parameters) that the user
can request and because each country can decide whether or not to allow
the telephone echange to offer a given service and because the
specifications that describe the services are open to interpretation in
many different ways.  So, as with other interoperability problems,
you must work with the vendors to determine if the equipment will
interoperate.  This is a basic problem; it impacts all ISDN
equipment, not just voice equipment.

The third has to do with homologation, or regulatory approval.  In most
countries in the world the manufacturer of telephone equipment must
obtain approvals before the equipment may be connected to the network.
So, even if the equpipment works with the network in a particular
country, it isn't OK to hook it up until the manufacturer has jumped
through the various hoops to demonstrate safety and compliance.  It is
typically more expensive to obtain world-wide homologation approvals
for a newly-developed piece of ISDN equipment than it is to develop it
and tool up to manufacture it.

There are attempts to remidy this situation, particularly for BRI
ISDN.  In North America, the National ISDN User's Forum is coming
up with standards that increase the uniformity of ISDN services.
In Europe, a new standard called NET3 is being developed.

[e-mail] (Ming Sun)
[e-mail] (Marco S Hyman)
[e-mail] (Jim Breen)
[e-mail] (Dave Evans)
[e-mail] (Oliver Jones)
[e-mail] (William Martin)
--------

25)  Will ISDN terminal equipment that works with one vendor's ISDN
     switch work properly when it is used with another vendor's switch?

[Ed. Note: The title is edited from the previous faq to try to fit in
  with the preceding question]
[Also, this seems to imply that there are only two implementations
 to worry about and it is very US-centric.  This section needs to be
 reworked]

Before National ISDN-1 is implemented, the ATT 5ESS switches and
Northern Telecom DMS100 switches speak different call setup dialogues.
That's why you will see ISDN TE listed as 5ESS, DMS100 or both.

[e-mail] (Jim Rees)
[e-mail] (Jerry Scharf)
--------

26) Do different manufacturers Terminal Adaptors interoperate when used
    asynchronously?

There is a standard up to 19.2k (V.110) but above that there is no real
standard implemented. However, in practice there is a fair degree of
interoperability (even when the TA's manual tells you otherwise)
because many TAs use the same chip set (supplied by Siemens) which
happily goes up to 38.4. TAs from different suppliers that are using
the Siemens chips have a fair chance of interoperating at up to 38.4k.

[e-mail] (William Martin)
--------

27) Why do I get only about 19.2k throughput from my TA?

The problems in using TA's are the same as those in using fast modems.
You only get the throughput that your serial port can handle. The
serial ports of many machines struggle to receive at 19.2k. Sending
seems to be easier. Many machines that will happily chuck data at a TA
at 38.4, but choke down to around 19.2k or l ower when receiving (with
lots of retries on ZMODEM file transfer).

[e-mail] (William Martin)
--------

28) How long should call setup take when using a TA?

The "less than a second" call setup sometimes claimed seems to be rare.
TAs have a negotiation phase and it typically takes around 4 seconds
to get through to the remote site.

[e-mail] (William Martin)
--------

29) Can I get on-line National ISDN information from Bellcore?

Information about National ISDN is now available by anonymous FTP (File
Transfer Protocol) over the Internet at host "info.bellcore.com". FTP
allows the retrieval of formatted documents and software.

The rest of this document assumes that you have access to a machine
connected to the Internet that supports FTP, and that you have a system
that can print both ASCII formatted documents and PostScript formatted
documents.

The files are available in PostScript through anonymous FTP from
"info.bellcore.com" in the /pub/ISDN sub directory.

I M P O R T A N T:  Many of the files are large, it is essential
that you first get the README (the upper case is important) file
for detailed information on retrieving various files associated with
documents.

The following text describes a typical anonymous FTP session:

  system: ftp info.bellcore.com <enter>
  Connected to info.bellcore.com.
  220 info FTP server (SunOS 4.1) ready.
  Name: anonymous <enter>
  331 Guest login ok, send ident as password.
  Password: <enter your internet login -- example: [e-mail]>
  230 Guest login ok, access restrictions apply.
  ftp> cd /pub/ISDN <enter>
  250 CWD command successful.
  ftp> mget README <enter>
  mget README? yes <enter>
  200 PORT command successful.
  150 ASCII data connection for README (8758 bytes).
  226 ASCII Transfer complete.
  local: README remote: README
  8943 bytes received in 0.19 seconds (46 Kbytes/s)
  ftp> quit <enter>
  221 Goodbye.

<enter> represents pressing the "enter" or "return" key on your
computer keyboard.

The README file is in ASCII format and may be read with most word
processors.  The other files in the directory are in PostScript format
and may be downloaded as needed by using the "mget" command while in
the FTP.

You should determine your local procedure for printing PostScript
documents.  For example, on many UNIX systems, PostScript files may be
printed on a PostScript printer by using the "lpr" command. A typical
Post Script print command may look like:

    lpr -P<printer> -h -v <filename.ps>

where:
    <printer> represents printer name accessable to your system, and
    <filename.ps> represents a PostScript file.

notes:
    '-h' corresponds to the option of suppressing the printing of
    burst page while '-v' corresponds to the option of printing
    raster image, i.e., PostScript. Please note that the printer
    must support PostScript imaging model in order to print these
    files.

Some systems are configured to detect PostScript formatted files
automatically, so a command to print the documents on that kind
of system is:

    lpr -P<printer> <filename.ps>

If you have problems or you'd like to comment on the information
stored at this site or wish to make recommendations for future
enhancements, you can send email to:

        [e-mail]

Or, call the Bellcore's National ISDN Hotline: [phone]-ISDN

A recent visit to the system revealed the following directories:

CATALOG:        NIUF (National ISDN User's Forum) catalog:
                "A Catalog of National ISDN Solutions for Selected NIUF
                Applications, Second Edition." [Ed: lots of big files,
                but some great info - chapter 4 is hundreds of pages of
                ISDN product/vendor information]
CONTACTS:       List of ISDN contacts at various Regional Bell Operating
                Companies
DEPLOYMENT:     Currently empty
EVENTS:         Info about the "ISDN Solutions '94" event
NATIONAL_ISDN:  Bellcore document SR-NWT-2006, "National ISDN"
                [Ed: I couldn't get this to print - what about you?]
README:         The Read Me File
TARIFF:         Currently empty

[e-mail] (sohl,william h)
--------

30)  Where can I read more?

"ISDN In Perspective"
Fred R. Goldstein
Addison-Wesley
ISBN 0-201-50016-7

[Ed. Note: the second edition is new...]
"ISDN: Concepts, Facilities, and Services, Second Edition"
Gary Kessler
McGraw-Hill, 1993 (2/e).
ISBN 0-07-034247-4

"Sensible ISDN Data Applications"
Jeffrey Fritz
[e-mail]
West Virginia University Press

"ISDN and Broadband ISDN" (2nd edition)
William Stallings
Macmillan
ISBN 0-02-415475-X

"Networking Standards: A Guide to OSI, ISDN, LAN and MAN Standards"
William Stallings
Addison-Wesley

"A Catalog of National ISDN Solutions for Selected NIUF Applications"
North American ISDN User's Forum
(use NIUF information above or order via Bellcore, document GP-1, $43)
 and/or see info on anonymous ftp to info.bellcore.com above)

The 1990 ISDN Directory and Sourcebook
Phillips Publishing Inc.
7811 Montrose Road
Potomac, MD  20854
[phone]

ISDN Sourcebook
Information Gatekeepers Inc.
214 Harvard Ave,
Boston, MA  02134
[phone]
1 800 323-1088

Bellcore National ISDN Specifications
SR-NWT-001953
SR-NWT-002361
SR-NWT-002120 (National ISDN-2)
US: 1-800-521-2673, other: 1-908-699-5800

Bellcore ISDN Availability Report
WR-NWT-2102 ($103)
US: 1-800-521-2673, other: 1-908-699-5800

AT&T Technical Journal special issue on ISDN
(Volume 65, Issue 1) January/February 1986

EFFector. Issue 2.01, Issue 2.06, Issue 2.08
ftp.eff.org:pub/EFF

AT&T Documents
--------------
"5ESS(rg.tm) Switch National ISDN Basic Rate Interface
Specification - 5E8 Software Release"
AT&T document number 235-900-341

"5ESS(rg.tm) Switch ISDN Basic Rate Interface
Specification - 5E7 Software Release" {Custom BRI}
AT&T document number 235-900-331

"5ESS(rg.tm) Switch ISDN Primary Rate Interface
Specification - 5E7 Software Release"
AT&T document number 235-900-332

"5ESS(rg.tm) Switch Interface Specification to a
Packet Switched Public Data (X.75) Network -
5E8 Software Release"  [as in CCITT X.75]
AT&T document number 235-900-317

"5ESS(rg.tm) Switch X.75' Intranetwork Interface
Specification - 5E8 Software Release"
  [as in Bellcore's TR-000310]
AT&T document number 235-900-325

"5ESS(rg.tm) Switch Documentation Description
and Ordering Guide"
  [list/description of 5ESS documents]
AT&T document number 235-001-001

AT&T documents ordering:
1-800-432-6600 USA
1-800-225-1242 Canada
[phone] elsewhere

AT&T Customer Information Center
Order Entry
2855 N. Franklin road
Indianapolis, IN 46219
[phone] (fax)

Northern Telecom Documents
--------------------------

NTP 297-2401-100        ISDN System Description
NTP 297-2401-010        ISDN Product Guide

---

31)  Who do I have to thank for this list?

Lots of people, in one way or another.

"Bob Larribeau" <[e-mail]>
[e-mail] (Eric Boll)
[e-mail]
[e-mail] (Helge Oldach)
[e-mail] (Jim Rees)
[e-mail] (Gary C. Kessler)
[e-mail] (Peter M. Weiss)
[e-mail] (Mathias Gaertner)
[e-mail] (Alan Palmer Stephens)
[e-mail] (Art Berggreen)
[e-mail] (Albert Willis)
[e-mail] (Gerhard Bernot)
[e-mail] (Ben Harrell)
blsouth![e-mail] (Michael Klein)
[e-mail] (Bob Clemmons)
[e-mail] (Dave Cherkus)
[e-mail] (Cliff Frost)
[e-mail] (Craig Partridge)
[e-mail] (Chuck Storry)
[e-mail] (Curt Welch)
[e-mail] (Dan Kegel)
[e-mail] (David L. Markowitz)
[e-mail]
[e-mail] (David E. Martin)
[e-mail] (Dror Kessler)
[e-mail] (Dwight Ernest)
[e-mail] (Greg Earle - Sun JPL on-site Software Support)
[e-mail] (Winston Seah)
[e-mail] (Eric A. Litman)
[e-mail] (Torsten Lif)
[e-mail] (Jim Fenton)
[e-mail] (Gary Martin)
[e-mail] (Giles Heron)
[e-mail] (Greg Larson)
[e-mail] (Fred R. Goldstein)
[e-mail] (Brad Huntting)
[e-mail] (James - The Keeper)
[e-mail] (Jerry Scharf)
[e-mail] (Jeffrey Fritz)
[e-mail] (Jamie Honan)
[e-mail] (Jonathan I. Kamens)
[e-mail] (Joe Smith)
[e-mail] (Rob Jordan)
[e-mail] (Jim Breen)
[e-mail] (TONY KENOW)
[e-mail] (Tom Kessler)
[e-mail] (Ketil Albertsen,TIH)
[e-mail] (Kevin Davis)
[e-mail] (Kevin Collins)
[e-mail] (Dave Evans)
[e-mail] (Dave Evans)
[e-mail] (Kevin Paul Herbert)
[e-mail] (Kevin J. Rowett)
[e-mail] (Laurence V. Marks)
[e-mail] (Marco S Hyman)
[e-mail] (Marc Evans)
[e-mail] (Mike Souryal)
[e-mail] (Ming Sun)
[e-mail] (Oliver Jones)
[e-mail] (Gerald L. Hopkins)
[e-mail] (Paul Antoine)
[e-mail] (Peter Ilieve)
[e-mail] ( Patton M. Turner)
[e-mail] (Patton M. Turner)
[e-mail] (Rachel Willmer)
[e-mail] (Randolph A. Sisto)
[e-mail] (Rob Davies)
[e-mail] (Russell Lang)
[e-mail] (Wade T. Rogers)
[e-mail] (Ronnie B. Kon)
[e-mail] (Sanjay Manandhar)
[e-mail] (Scott Colwell)
[e-mail] (Scott Turner)
[e-mail] (Keith Sklower)
[e-mail] (winston (w.l.) sorfleet)
[e-mail] (Joe Ilacqua)
[e-mail] (Toby Nixon)
[e-mail] (Andrew Scherpbier)
[e-mail] (Al Varney)
[e-mail] (David Lesher)
[e-mail] (Sean N. Welch)
[e-mail] (sohl,william h)
[e-mail] (William Martin)

----
Dave Cherkus          UniMaster, Inc.         [e-mail]
--
Dave Cherkus          UniMaster, Inc.         [e-mail]