Question 11/XII - Transmission degradation introduced by interaction
between voice operated devices
(continuation of Question 11/XII studied in 1985-1988; new wording)

Considering

- that international network configurations can contain a combination of
voice operated devices such as:

- acoustical or electrical echo control devices, speech interpolation
devices, DCME, packetizing devices, etc.

the following Questions should be studied:

1. What are the network configurations of particular interest needing
testing priorities?

2. How is the transmission quality of a network configuration impaired
by:

-such devices, acting in tandem, or in association with each other, and
by

-the interaction of these devices with other relevant connection
characteristics (loss, noise (stationary or changing), echo path loss
and delay, etc. ...),

3. What are the most appropriate testing methodologies able to evaluate
and compare the transmission degradation induced in the different
network configurations?

4. What are the maximum overall performance degradations acceptable for
these network configurations in conjunction with subscriber expectations
(see for example Note 1, 2.2 in Recommendation G.131)?

5. What other considerations and possible limitations can be introduced
by voice band data transmission, if any?

Note - A liaison will have to be established with the Questions dealing
with transmission quality evaluation of equipment listed in the wording
of Q.11/XII.