Question 14/VII - Interworking between public data networks and the
telex networks (continuation of Question 19/VII studied in 1985-88)

Considering

(a) that administrations are currently operating PDNs and the telex
network;

(b) that Study Group VII has the responsibility for studying the
definitions and procedures for interworking between PSPDNs and the telex
network;

(c) that Recommendation F.73 gives the operational and service
principles for communication between terminals on the telex network and
data terminal equipment on a packet switched public data network,

1. What new Recommendation(s), and additions or modifications to
existing Recommendation(s) are necessary to enable PSDNs to interwork
with the telex network for interworking involving both communication and
transmission capability?

Draft Recommendation X.340 which gives the principles for this type of
interworking should be the basis for further study on the subject, and
is reproduced in Annex 1. The following topics have been identified:

a) satisfying the service requirements described in Recommendation F.73;

b) compatibility with the technical requirements for the telex network
described in draft Recommendation U.203;

c) use of alternative forms of conveying telex numbers in accordance
with X.121;

d) the method of break handling may be optional and enhanced to cover
counterwriting;

e) permit use of command and service signals;

f) the need for explicit X.29 protocol identifier;

g) network options for packet forwarding criteria;

h) possible translation of WRW to ENQ and inhibiting IWF Answerback
prior to connection phase;

i) other mechanisms to indicate that the IWF is no longer able to accept
additional characters;

j) determination of an X.3 parameter profile and identification of which
parameters should be changeable.

2. Is there a need for PSPDN to telex interworking involving
communication capability? If so, what new Recommendation(s), and
additions or modifications to existing Recommendation(s) are necessary?

3. Is there a need for CSPDN to telex interworking? If so, what new
Recommendation(s), and additions or modifications to existing
Recommendation(s) are necessary?

4. The following liaisons should be maintained in this study:

a) general principles and arrangements for interworking between PDNs and
between PDNs and other public networks are being studied in Study Group
VII;

b) procedures to be used on the telex network are being studied in Study
Group IX;

c) service principles for interworking are being studied in Study Group
I.

ANNEX 1

(to Question 14/VII)