Actions
  • Title
    Collection of sales documentation and technical manuals relating to the BT Monarch Call Connect System digital PABX (private automatic branch exchange)
  • Reference
    MS/2186
  • Production date
    1980 - 1996
  • Creator
    • British TelecomBiography
  • Scope and Content
    Monarch was developed from 1976 by a Post Office research team, working at first at Dollis Hill and later at Martlesham, together with the telecommunications industry, at the same time that the System X digital exchange was being developed for the public network. The first trial local System X exchange went into service at Woodbridge, Suffolk, in 1981 and the first System X main exchange was installed in 1983. By 1987 virtually all the main switching units had been converted to digital, comprising some 55 main exchanges. By 1988 local exchanges were being converted to System X in large numbers. (System Y, an alternative digital exchange system, was also being installed in many local exchanges.) The British network was entirely digital by 1998. System X was a great success technically, although export orders were few, largely owing to political issues arising from management of its production development among several manufacturers. The Monarch 120 PABX system first went into service in 1980 and aspects of its circuit design had a crucial influence on System X development. It was one of the first all-digital PABX systems in the world.
  • Extent
    7 items
  • Language
    English
  • Level of description
    TOP
  • Repository name
    Science Museum, London
  • Conditions governing access
    Open Access
  • Conditions governing Reproduction
    Copies may be supplied in accordance with current copyright legislation and Science Museum Group terms and conditions
  • Related object
  • Related items
    2015-490
    2015-489
    2015-488