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IMPORT
R:\\ART\\W INTERNATIONAL TELECOMMUNICATION UNION
MF\\ITU.WM
F \*
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t
CCITT F.87
THE INTERNATIONAL
TELEGRAPH AND TELEPHONE
CONSULTATIVE COMMITTEE
TELEGRAPH AND MOBILE SERVICES
OPERATIONS AND QUALITY OF SERVICE
OPERATIONAL PRINCIPLES FOR THE
TRANSFER OF MESSAGES FROM
TERMINALS ON THE TELEX NETWORK
TO GROUP 3 FACSIMILE TERMINALS
CONNECTED TO THE PUBLIC SWITCHED
TELEPHONE NETWORK
Recommendation F.87
IMPORT Geneva, 1991
R:\\ART\\
WMF\\CCIT
TRUF.WMF
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at
Printed in Switzerland
FOREWORD
The CCITT (the International Telegraph and Telephone Consultative
Committee) is a permanent organ of the International Telecommunication Union
(ITU). CCITT is responsible for studying technical, operating and tariff
questions and issuing Recommendations on them with a view to standardizing
telecommunications on a worldwide basis.
The Plenary Assembly of CCITT which meets every four years, establishes
the topics for study and approves Recommendations prepared by its Study Groups.
The approval of Recommendations by the members of CCITT between Plenary
Assemblies is covered by the procedure laid down in CCITT Resolution No. 2
(Melbourne, 1988).
Recommendation F.87 was prepared by Study Group I and was approved under
the Resolution No. 2 procedure on the 11 of March 1991.
___________________
CCITT NOTE
In this Recommendation, the expression "Administration" is used for
conciseness to indicate both a telecommunication Administration and a recognized
private operating agency.
F ITU 1991
All rights reserved. No part of this publication may be reproduced or utilized in
any form or by any means, electronic or mechanical, including photocopying and
microfilm, without permission in writing from the ITU.
PAGE BLANCHE
Recommendation F.87
Recommendation F.87
OPERATIONAL PRINCIPLES FOR THE TRANSFER OF MESSAGES FROM TERMINALS
ON THE TELEX NETWORK TO GROUP 3 FACSIMILE TERMINALS CONNECTED
TO THE PUBLIC SWITCHED TELEPHONE NETWORK
The CCITT,
considering
(a) the need to allow the transfer of messages from terminals of the
international telex service to Group 3 facsimile terminals on the public switched
telephone network;
(b) that Recommendations F.60, F.69 and other relevant Recommendations
govern operation of the international telex service;
(c) that Recommendation E.163 defines the numbering plan for the
international telephone service;
(d) that Recommendation F.72 defines the general principles and operational
aspects of international telex store and forward;
(e) that Recommendations F.160 and F.180 define the general operational
provisions for the international public facsimile services;
(f) that Recommendation T.4 defines the standardization of Group 3
facsimile apparatus;
(g) that Recommendation T.30 defines the procedure for document facsimile
transmission in the public switched telephone network;
(h) that technical aspects of the international telex service are described
in R-, S- and U-Series Recommendations,
unanimously declares the view
(1) that there are benefits in standardizing the operational procedures for
a terminal of the international telex service to transfer a message, across
international boundaries, to a Group 3 facsimile terminal on the public switched
telephone network;
(2) that where this message transfer service is provided, the preferred
operational procedures are laid down in this Recommendation.
1. Scope
1.1 The procedures defined in this Recommendation enable telex subscribers to
transfer messages to Group 3 facsimile terminals connected to the PSTN, on a
store and forward basis.
1.2 The interworking shall be established by provision of a telex/facsimile
interworking function (FAXIWF).
1.3 International access to the FAXIWF will normally be provided via the telex
network (see Figure 1/F.87). Bilateral agreement may be required in the event
that other than normal telex service agreements are required.
1.4 For telex subscribers accessing a FAXIWF in their own country, national or
international destinations may be specified, with international interworking
being implemented via the PSTN. See Figure 2/F.87.
Figure 1/F.87 = 7,5 cm
Figure 2/F.87 = 8 cm
1.5 The Administration providing the FAXIWF shall be responsible for any
necessary barring of international access.
2. Service principles
2.1 The basic service offered is:
ù acceptance of messages from the telex network, with accompanying fax
(PSTN) addressing information;
ù delivery of these messages to the requested facsimile terminal, with
retries if necessary;
ù notification message sent to the originator when the message delivery
attempt fails and, optionally, when it succeeds.
2.2 A single-stage selection procedure may be used employing normal telex
procedures where the requested facsimile machine is addressed using a telex
number.
2.3 A two-stage selection procedure may be used whereby a call from the telex
network gains access to the FAXIWF in the first stage of selection and inputs the
called address(es) and message(s) in the second stage of selection, after the
return of a call connect signal. To the extent possible, this procedure has been
aligned with that for telex store-and-forward facilities defined in
Recommendation F.72.
2.4 Message input from both manual and telex automatic emitting devices should
be possible.
2.5 Messages deposited into the FAXIWF will be sub-divided by the FAXIWF into
"pages" which serve as physical "A4" size pages as received at the fax terminal.
styleref head_footRecommendation F.87PAGE
7
Otherwise, the input format shall be preserved.
A page should normally comprise 55 lines of text (of 4.23 mm pitch), or
part thereof for pages with fewer than 55 text lines. Upon transmission, it is
preferred to have both message reference and pagination information inserted in a
header line on each page.
2.6 In addition to delivering the message as pages of text to the specified
fax terminal(s), the FAXIWF may optionally prepare and transmit a "header page"
consisting of at least:
ù message reference information (which may include the legal time and
date of acceptance);
ù calling party identification (telex answerback and recall information,
if necessary);
ù indication of number of pages in message;
ù specified facsimile terminal (PSTN) address;
ù optional customer attention information field (see S 3.2.4).
2.7 Where a header page is not transmitted, the FAXIWF should attach a herald
to the beginning of the message indicating the calling party identification
(telex answerback and recall information, if necessary).
2.8 The FAXIWF will attempt to deliver the message as soon as operationally
feasible. Deferred delivery may also be provided.
3 Service facilities
In the following section, the symbol * indicates that the facility is not
normally applicable for one-stage selection.
3.1 General
In addition to message deposit, the following facilities may be made
available:
ù multi-address*;
ù follow-on messages*;
ù positive delivery notification;
ù status enquiry request;
ù message cancel request*.
Note ù The multi-address facility would not normally be available to
incoming international telex calls except by bilateral agreement.
3.2 Message deposit
3.2.1 Validation of format and/or length should preferably be performed by the
FAXIWF on the address(es) of the called fax terminal(s) as specified by the
calling party.
3.2.2 Where the multi-address facility is provided, the FAXIWF should be capable
of accepting at least 20 facsimile terminal (PSTN) addresses in a multi-address
call.
PAGE6 styleref head_footRecommendation F.87
3.2.3 An attention information field facility should be provided by the FAXIWF
to enable each addressee of a multi-address message to have a relevant attention
prefix preceding the message in the header page where such is provided.
3.2.4 A message reference number shall be available to the calling party for
every message accepted by the FAXIWF. For multi-address messages, a separate
message reference number may be provided for each address.
3.2.5 The application of short-code address* and pre-recorded address lists is a
national matter.
3.3 Follow-on messages
Provision may be made to accept follow-on message(s) with their associated
address(es) which may be sent immediately after the deposit of a previous message
while still retaining the connection to the FAXIWF from the originator. The
procedures should be aligned with Recommendation U.43.
3.4 Status enquiry request
3.4.1 Status information on previously-deposited message shall only be returned
to the message originator. The procedure used should be generally aligned with
Recommendations F.72 and U.80.
3.4.2 This status information should be available for at least 24 hours after
the time of message receipt by the FAXIWF.
3.5 Message cancel request*
If message cancellation is provided, previously deposited messages may
only be cancelled by the message originator.
3.6 Delivery/non-delivery notification message and journals
3.6.1 In the case of failure to deliver a message to the requested fax terminal,
the FAXIWF shall if possible return a non-delivery notification message to the
originator (see S 7.1).
3.6.2 An Administration may optionally provide a positive delivery notification
message to the originator upon successful delivery of the message to the
requested fax terminal (see S 7.2).
3.6.3 The above notifications may also be provided in a summarized form
(journals).
4 Access procedures
4.1 General
Two basic procedures for access from a telex terminal should be provided
by the FAXIWF:
a) Interactive operation:
ù input from manual calling terminals where the TPIWF may return
prompt signals;
b) Non-interactive operation:
ù input from telex automatic emitting devices where prompt signals
may not be required;
ù interworking with other types of interworking and conversion
facilities.
4.2 One-stage selection
In the one-stage selection procedure, the facsimile terminal is assigned a
telex number that is part of the national telex numbering plan.
styleref head_footRecommendation F.87PAGE
7
4.2.1 Call establishment
4.2.1.1 The originator (or intermediary interworking or conversion facility)
shall use normal telex procedures.
4.2.1.2 The telex number received by the FAXIWF shall be verified as being
proper to a registered facsimile terminal. The method of effecting this
verification is a national matter. If the verification fails, the following
procedures should be applied:
a) where the FAXIWF is provided by the Administration which also provides
all or part of the telex network, the service signal NP may be
returned;
b) where the FAXIWF is not provided by the Administration which also
provides all or part of the telex network, the procedures to be applied
shall be in accordance with Recommendation F.74.
4.2.1.3 Having verified the received telex number, the FAXIWF shall return the
answerback allocated to the requested facsimile terminal to the originator.
4.2.1.4 This answerback of the facsimile terminal shall be formatted in
accordance with Recommendation F.74.
4.2.1.5 In accordance with Recommendation S.23, the FAXIWF may transmit a WRU
signal to the originating telex subscriber if the backward path remains idle for
at least 800 milliseconds.
4.2.1.6 Having received the answerback allocated to the called facsimile
terminal, the originator may input the text of his message. The FAXIWF shall
respond to any received WRU signal during this phase of the call by returning the
answerback allocated to the facsimile terminal.
4.2.1.7 The reaction to abnormal conditions during call set-up shall be in
accordance with normal telex procedures (see Recommendation U.2071) ).
4.3 Two-stage selection
4.3.1 General
4.3.1.1 Calls to the FAXIWF will be established by means of normal telex
procedures.
4.3.1.2 The received telex answerback shall be processed in accordance with
Recommendation U.74 to determine the calling telex address. If the answerback is
deemed to be non-processable, the FAXIWF shall request input of the calling
address by the telex subscriber by returning the ADD prompt.
4.3.1.3 Transmission from an automatic terminal is indicated by commencing the
procedure with the non-interactive service request (characters CI). The calling
terminal is recognized as interactive by the omission of the non-interactive
service request (CI).
4.3.1.4 If the calling telex address is capable of being extracted from the
received answerback, the FAXIWF shall return GA, unless a non-interactive service
request has been made.
4.3.2 Input of address(es)
4.3.2.1 For each address required, the originator should transmit the sequence
FAX <address> + (<optional attention information field>)
where:
FAX is the service identifier.
4.3.2.2 The address field <address> is the only mandatory field of the address
line and is the called PSTN fax address formatted in accordance with
Recommendation E.163. The address field consists of the international PSTN number
of the required fax terminal. The end of the address field should be delimited by
the end of address field signal (+), for example,
P43150145207+
1) Recommendation U.207 has not been officially approved as of the publication date
of this Recommendation F.87.
PAGE6 styleref head_footRecommendation F.87
The attention information field is a 30-character field, delimited by
parentheses, for example:
(ATTN: MR.J.SMITH)
The inclusion of the field is optional. If specified, the field will be
inserted in the header page (see S 3.2.3), otherwise that part of the header page
will be left blank.
An example of a complete address line would be as follows:
FAX 43150145207+(ATTN: MR.J.SMITH)
4.3.2.3 The last address line shall be delimited from the message by the end of
address sequence/begin text input sequence BT.
4.3.2.4 It should be possible to mix telex, teletex and facsimile addresses in
a multi-address call in accordance with Recommendation F.72.
4.3.2.5 Once the maximum number of permissible addresses have been input,
the FAXIWF shall return the message input prompt (GA) unless a non-interactive
service request has been received.
4.3.2.6 If an end-of-address signal (BT) is received without any valid
addresses being received, the call will be cleared by the FAXIWF.
4.3.2.7 The action to be taken when invalid addresses are received shall be in
accordance with S 5.2.3.
4.4 Answerbacks and WRU processing
4.4.1 In the case of single-stage selection, the FAXIWF shall at all times
respond to the reception of a WRU signal from the originator with the
"answerback" allocated to the registered terminal, formatted in accordance with
Recommendation F.74.
4.4.2 In the case of two-stage selection, the FAXIWF shall at all times respond
to a received WRU signal with its own answerback, consisting of 20 characters
formatted in accordance with Figure 3/F.87 and Recommendation F.60 where F is the
TNIC of the network to which the FAXIWF is connected. Neither the WRU signal nor
the resultant answerback should be stored as part of the message.
Figure 3/F.87 = 3 cm
5 Message deposit by the telex subscriber
5.1 General
5.1.1 All ITA2 spacing characters received during text input shall be stored by
the FAXIWF for subsequent transmission to the addressed facsimile terminal.
However, neither the WRU signal nor the bell signal, if received as part of the
text, will be stored within the message.
5.1.2 The FAXIWF shall be able to accept messages of at least 24 000 characters.
5.1.3 If the calling subscriber wishes to cancel a message during the text input
phase, the cancel operation signal to be used, where the FAXIWF offers this
facility, is FFFF.
If the FAXIWF detects a cancel operation signal, it should cease message
acceptance, issue the message cancel confirmation signal ANUL ANUL and clear the
call.
5.1.4 In case of two-stage selection, if the FAXIWF detects a valid EOM or EOT
signal, but no characters have been received as message text, the message will be
abandoned and, if not already cleared by the originator, the call shall be
cleared by the FAXIWF as in S 5.1.3.
5.1.5 The reaction to abnormal conditions during message deposit shall be in
accordance with Recommendation U.2071).
5.2 Message security
5.2.1 The FAXIWF should only accept messages for delivery to destination
addresses accessible from that FAXIWF.
5.2.2 In case of two-stage selection, the FAXIWF should not accept message input
unless acceptable identification of the originator has been received at call set
up.
5.2.3 The FAXIWF may verify the format of the called address(es). If this
verification is unsuccessful for all addresses, the message shall be rejected and
the service code ITR should be returned (see Recommendation U.80, S 4.6).
However, a positive verification result does not guarantee that the message can
be delivered to the given address.
5.3 End of transaction and end of message signal
5.3.1 At the end of each transaction, an end of transmission (EOT) signal is
required. This signal is + + + +. However, for follow-on messages, an end of
message (EOM) signal is required at the end of each individual message. This can
be one of two types, as follows:
a) NNNN, which is simply used to separate messages;
b) NNNNACK, which is used to separate messages and to request the FAXIWF
1) Recommendation U.207 has not been officially approved as of the publication date of
this Recommendation F.87.
styleref head_footRecommendation F.87PAGE
7
for an input message acknowledgment (IMA) plus reference information of
those messages not previously acknowledged.
5.3.2 Where there is a stop in transmission for 30 seconds, and no EOM or EOT
signal is detected, the service code GA will be sent to the originator.
5.3.3 If the EOM/EOT signal is not received, or transmission does not resume
within a further 30 seconds, the FAXIWF shall initiate the clear down procedure.
5.3.4 In case of two-stage selection, a message received without any EOM or EOT
shall nevertheless be delivered with the following text appended: POSSIBLE
INCOMPLETE MESSAGE.
5.4 Input transaction accepted
The FAXIWF shall send an input transaction accepted code for
delivery (ITD) notifying the originator that the message(s) has(have) been
accepted and that delivery would be attempted. Delivery should be attempted even
if the call is cleared before the ITD is sent. The ITD should be followed by the
message reference(s) and, if applicable, number of messages.
6 Message delivery
6.1 Messages deposited in the FAXIWF with appropriate PSTN address(es) shall
be delivered as soon as operationally feasible after receipt, unless deferred
delivery option is requested. Delivery to the requested fax terminal(s) shall be
in accordance with the normal procedures applicable to fax-fax communication (see
Recommendation T.30).
6.2 If the delivery attempt is unsuccessful, i.e. the complete message was not
delivered, the FAXIWF may initiate re-attemps in accordance with national rules
laid down for re-calling into the PSTN.
PAGE6 styleref head_footRecommendation F.87
6.3 Should all delivery attempts fail, the FAXIWF shall return a non-delivery
notification message to the originator in accordance with S 7.1.
6.4 Should delivery be successfully completed, the FAXIWF may return a
positive delivery notification message to the originator where this facility is
offered by the Administration operating the FAXIWF.
6.5 Where a message is only partially delivered, i.e., the connection across
the PSTN was cleared for any reason before the EOM or EOT was reached, the FAXIWF
shall re-establish the connection and re-send the message commencing after the
last successfully delivered page.
6.6 The reaction to abnormal conditions during message delivery shall be in
accordance with the relevant
E- and T-Series Recommendations.
7. Delivery/non-delivery notification messages
7.1 Non-delivery notification message
7.1.1 The FAXIWF shall return a non-delivery notification message to the
originator in respect of failure to deliver an accepted message in its entirety
to any requested destination.
7.1.2 The non-delivery notification message should be returned to the
originating telex subscriber as soon as possible after expiry of the retry cycle
(see S 6.2 above).
7.1.3 It is recommended that the message contain at least the following
information:
ù message reference;
ù time/date of message acceptance by the FAXIWF;
ù time/date of final delivery attempt;
ù originating telex answerback;
ù requested facsimile terminal number;
ù called station identity (CSI), if available;
ù number of delivery attempts made;
ù number of pages transmitted.
7.1.4 If the FAXIWF is unable to deliver the non-delivery notification message
to the originating subscriber after a maximum of 8 attempts to do so, the message
should be spilled out to an assistance position for manual processing.
7.2 Positive delivery notification message
7.2.1 An Administration may optionally offer this facility to its subscribers
either on a global basis or by request by the calling subscriber at the
addressing stage.
7.2.2 The facility may be requested on a per-address basis by use of the ACK
signal in the address line, as follows:
FAX <Address>+(optional information field),ACK
for example:
FAX 43150145207+(ATTN: MR.J.SMITH),ACK
7.2.3 It is recommended that the positive delivery notification message, where
provided, contain at least the following information:
ù message reference;
ù time/date of message acceptance by the FAXIWF;
ù time/date of final delivery attempt;
ù originating telex answerback;
ù requested facsimile terminal number;
styleref head_footRecommendation F.87PAGE
7
ù called station identity (CSI), if available;
ù number of pages in message;
ù number of delivery attempts made;
ù number of pages transmitted.
7.2.4 If the FAXIWF is unable to deliver the positive delivery notification
message to the originating subscriber after a maximum of 8 attempts to do so, the
message should be spilled out to an assistance position for manual processing.
ANNEX 1
(to Recommendation F.87)
List of abbreviations
ACK Request for positive delivery notification
ADD Address prompt
BT End-of-address/begin text signal
CI Conversation impossible
CSI Called station identity
EOM End-of-message
EOT End-of-transaction
FAXIWF Facsimile interworking function
GA Go ahead
IMA Input message acknowledgment
ITD Input transaction accepted for delivery
ITR Input transaction rejected
PSTN Public switched telephone network
TNIC Telex network identification code
WRU Who-are-you
PAGE6 styleref head_footRecommendation F.87
