BS 6450-4:1993 Private branch exchanges for connection to public switched telephone networks run by certain public telecommunications operators - Specification for ports
1 This Part of BS 6450 specifies requirements for private branch exchanges (PBXs) having ports that may be connected to one or more of the following:
a) two or more public exchange lines;
b) private leased circuits run by a public telecommunications operator (PTO);
c) private links.
The ports within the scope of these requirements are those for connection to:
1) any of the public switched networks run by a PTO;
2) private leased circuits run by a PTO;
3) telecommunications apparatus of any description, specifically approved for connection to a PBX;
4) privately provided links, including links to other apparatus within the scope of these requirements;
5) approved accessories and other approved apparatus whose approval does not provide specifically for connection to a PBX.
2 The requirements do not cover all of the features or facilities with which a PBX could be equipped.
3 The requirements do not apply to PBXs for connection to shared service lines or 1 + 1 carrier systems.
4 The requirements enable a PBX to have, connected in parallel at 2-wire presented analogue exchange line ports, apparatus whose ringer equivalence number (REN) does not exceed 0.3 (see 4.2 of BS 6305 : 1992).
NOTE 1. Unless otherwise stated, all clause references refer to this Part of BS 6450. Where reference is made to a particular clause of another publication, the requirements contained in that clause are applicable irrespective of the scope of that publication. Any clauses of another publication not specifically invoked do not apply.
NOTE 2. Recommendations for the installation of PBXs, including wiring, are given in BS 6701: Parts 1 and 2.
5 This Part of BS 6450 does not of itself specify the complete requirements for a particular PBX and needs to be read in conjunction with other Parts of BS 6450 as appropriate.
BS 6450-4:1993 history
1998BS 7378-3:1998 Apparatus for connection to public telecommunications systems using the Digital Access Signalling System No. 2 (DASS 2) via a 2048 kbit/s CCITT Recommendation G.703 interface - Requirements for apparatus for connection to Channel Associated Signalling Sys
1993BS 6450-4:1993 Private branch exchanges for connection to public switched telephone networks run by certain public telecommunications operators - Specification for ports