11. Private branch exchanges for connection to public switched telephone networks run by certain public telecommunication operators. Specification for general requirements Part 1, (1st September 1988) Authors: British Standards Institution, Record Type: Book Extent: 1 online resource (27 pages) View Content: Available online (eLD content is only available in our Reading Rooms) ↗
12. Private branch exchanges for connection to public switched telephone networks run by certain public telecommunication operators. Specification for private branch exchanges with terminating stations treated as an entirety Part 2, (1st September 1998) Authors: British Standards Institution, Record Type: Book Extent: 1 online resource (19 pages) View Content: Available online (eLD content is only available in our Reading Rooms) ↗
13. Private branch exchanges for connection to public switched telephone networks run by certain public telecommunication operators. Specification for the procedure for in-service observation of PBXs undergoing type approval Part 7, (28th October 1990) Authors: British Standards Institution, Record Type: Book Extent: 1 online resource (14 pages) View Content: Available online (eLD content is only available in our Reading Rooms) ↗
14. Private branch exchanges for connection to public switched telephone networks run by certain public telecommunication operators.Facilities on private branch exchanges. Specification for facilities on private branch exchanges with terminating stations treated as an entirety Part 5-5.1, (30th September 1988) Authors: British Standards Institution, Record Type: Book Extent: 1 online resource (40 pages) View Content: Available online (eLD content is only available in our Reading Rooms) ↗
15. Private branch exchanges for connection to public switched telephone networks run by certain public telecommunications operators. Specification for general requirements Part 1, (15th February 1993) Authors: British Standards Institution, Record Type: Book Extent: 1 online resource (40 pages) View Content: Available online (eLD content is only available in our Reading Rooms) ↗
16. Private branch exchanges for connection to public switched telephone networks run by certain public telecommunications operators. Specification for ports Part 4, (15th December 1993) Authors: British Standards Institution, Record Type: Book Extent: 1 online resource (162 pages) View Content: Available online (eLD content is only available in our Reading Rooms) ↗
17. Private branch exchanges for connection to public switched telephone networks run by certain public telecommunications operators. Specification for private branch exchanges with terminating stations treated as an entirety Part 2, (15th February 1993) Authors: British Standards Institution, Record Type: Book Extent: 1 online resource (32 pages) View Content: Available online (eLD content is only available in our Reading Rooms) ↗
18. Scenarios for interconnections between exchanges of private telecommunication networks. (28th June 1991) Authors: British Standards Institution, Record Type: Book Extent: 1 online resource (20 pages) View Content: Available online (eLD content is only available in our Reading Rooms) ↗