Digital Private Network Signalling System: Difference between revisions

Revision as of 10:17, 9 April 2011

Revision as of 15:54, 28 April 2011

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In practice, DPNSS was possibly a backroom development by a couple of guys at BT's research labs whose efforts accidentally found a market and official support.{{Citation needed|date=April 2011}}

BT and some of the UK manufacturers championed DPNSS into ECMA and CCITT (ITU) but it was eventually deprecated by the standards bodies in favour of Q931 and QSig. Nevertheless, the elegance of the protocol and its compatibility with PBX features ensured the adoption DPNSS actually grew in Europe, compared to the much slower take-up of Qsig.

Version 1 of BTNR188 (DPNSS) was issued in 1983; the last version of DPNSS to be released 6 in 1995 included compatibility with ISDN features released in V5. A lightweight version of DPNSS 'APNSS' was developed forusing smalleranalogue PBXstrunks (Sometimes compressed) and a modem to support D channel signalling.

==Overview of the Protocol==