Question 10/XV - Characteristics of Digital Circuit Multiplication
Equipment
(DCME) and Systems (DCMS)
(Continuation of Questions 13/XV and 31/XVIII, 1985-1988)

Considering

(1) that Recommendation G.763 currently addresses the functional
requirements for a DCME based on the encoding algorithms of
Recommendations G.721 and G.723;

(2) that this Recommendation has outstanding items and provisional
values;

(3) that the intent is to provide a Recommendation which will ensure
full compatibility between equipments made by different manufacturers;

(4) that the Recommendation is intended to be applicable to both
satellite and cable systems and should include point-to-point and
multipoint applications and the various signalling systems;

(5) that the information currently available to the CCITT includes that
in the documents listed in Supplement 1 to Recommendation G.763;

(6) that administrations and other authorities are also studying
detailed specifications for DCME and DCMS;

(7) that there may be a future Recommendation for a 16 kbit/s speech
encoding algorithm (see Question 21/XV),

1. How should Recommendation G.763 be expanded and finalized while
achieving full compatibility for the various applications?

2. How should studies of DMCE in the CCITT be coordinated with those
being carried out by other authorities?

3. What should be recommended in DCME to ensure correct operation of a
DCMS in a network, e.g. ISDN?

4. How should Recommendation G.763 be modified and what new
Recommendations may be desirable considering the algorithms which may
result from the study of Question 21/XV?

5. Is 16 kbit/s overload channel operation desirable, and if so, how
should Recommendations G.723 and G.763 be modified to accommodate this?

Points for study

1.Network considerations and constraints affecting the DCME design.

2.Equipment implications of tandem operation of DCMS in a network.

3.DCME frame structure and protocols.

4.Slip buffer effects.

Notes

1. The study of this Question should be coordinated with:

1.1 Study Group XII on subjective testing issues.

1.2Study Group XI on network telephone switching and signalling issues.

1.3Study Group XVIII on general network issues.

2. Operations, Administration and Maintenance interfaces on transmission
equipment are studied under Question 9/XV.

3. The study of this Question should start with the INTELSAT, EUTELSAT
and T1 specifications used as basic source documents, together with any
further contributions from other bodies and administrations both for
setting study priorities and as technical proposals.