Integrated Services Digital Network (ISDN); Call Hold (HOLD) supplementary service; service description; english version ETS 300139:1992
Edition 1992-12

Transmission and Multiplexing (TM) - Synchronous cross connection equipment 64 and n × 64 kbit/s cross connection rate 2048 kbit/s access ports - Part 2: Management aspects; English version ETS 300010-2:1997
Edition 1997-12

Signalling Protocols and Switching (SPS) - Q3 interface at the Local Exchange (LE) for configuration management of V5 interfaces and associated customer profiles - Part 2: Managed Object Conformance Statement (MOCS) proforma specification; English version ETS 300377-2:1995
Edition 1996-07

Extensions for Financial Services (XFS) interface specification - Part 1: Application Programming Interface (API): Service Provider Interface (SPI); programmer's reference; English version CWA 13449-1:1998
Edition 1999-03