Question 20/XVIII - Layer 1 characteristics of ISDN interfaces and ISDN
access

Considering

(a) existing Recommendations dealing with Layer 1 characteristics of
ISDN interfaces;

(b) ongoing studies related to the support of mobile and broadband
services in ISDNs and to the network node interfaces taking account of
the new Synchronous Digital Hierarchy;

(c) there is a need to amend existing Recommendations and to define the
Layer 1 characteristics of new interfaces;

the following should be studied:

1. What Recommendations are required for Layer 1 characteristics of
broadband ISDN user-network interfaces?

2. What revisions need to be made to existing Layer 1 user-network
interface Recommendations (I.430/I.431)?

3. What extensions, if any, are needed for user-network interfaces to
cater for mobile services?

4. What characteristics should be recommended for digital line systems
on metallic pairs to be used in the local network (choice of options and
enhancements to Recommendation G.961)?

5. What characteristics should be recommended for broadband ISDN
customer access in local networks?

6. What new Recommendations are required for the characteristics of
digital sections for subscriber access (Note 3)?

7. What additions need to be made, if any, to Recommendations on network
interfaces to private networks including subscriber premises equipment,
e.g. home electronic systems?

Note 1 - In the course of preparation of Recommendations, the eventual
requirements for conformance testing should be borne in mind.

Note 2 - The Layer 1 specifications should take into account EMC and
safety aspects being studied by Study Group V.

Note 3 - The work on digital sections for subscriber access may require
enhancement of the V-interface Recommendation G.512. Therefore close
cooperation with Study Group XI is necessary.