Question 30/XII - Methods for evaluating the transmission performance of
digital telephone sets
(continuation of Question 38/XII studied in 1984-88)

Considering

(a) that digital telephone sets are already under development for public
and private extension networks, and are beginning to appear on the
market;

(b) that the desirable transmission performance characteristics of
digital telephone sets are under study in Question 10/XII;

(c) that current digital telephone sets are based on the use of 64
kbit/s PCM encoding (A or m5 -Law), and other encoding schemes are
currently being used or developed by some administrations;

(d) that only a provisional Recommendation P.66 exists for verifying
their performance characteristics,

The CCITT decides to study the following Questions:

1. What further methods can be specified for evaluating the transmission
performance of digital telephone sets to complete the Recommendation
P.66 and how should it be amended to meet the needs for future
development?

2. What digital access point and interface should be used for testing
purposes?