Rec. ITU-T Q.115 (03/1993) … CONROL OF ECHO SUPPRESSORS - CONTROL OF ECHO SUPPRESSORS AND ECHO CANCELLERS
FOREWORD
CONTENTS
1 General
2 Use of different signalling systems for one connection with respect to echo control
3 Terminology
4 Compatibility of echo control devices and in-band signalling systems
5 Operation without signals
6 Analysis of information at an outgoing exchange
7 Decision to be taken at the outgoing exchange
8 Decision to be taken at a transit exchange
9 Decision to be taken at the incoming exchange
10 Unavailability of echo control devices
    10.1 Association of echo control device to circuits
11 Handling of ECDs in the case of different connection types
    11.1 PLMN to PSTN or ISDN interworking
12 Control of ECD if Signalling System No. 7 ISUP is used
    12.1 Analysis of additional information provided by ISUP
    12.2 Propagation delay counter, call history information
13 Other considerations
Annex A … Call processing logic … Echo suppressor control
Annex B … Echo suppressor control on inter-ISC circuits within a single country
Annex C … Echo control for ISDN basic and supplementary services
C.1 Call diversion services
C.2 Multi-party services
References