Confravision

Confravision was an early British studio-based city-to-city videoconferencing service in the United Kingdom, launched in 1971 by Post Office Telecommunications.[1][2][3] In 1972, Confravision was available between studios in Bristol, Birmingham, Glasgow, London, and Manchester.[4]

The studio locations were:

  • Euston Tower[4]
  • 2-12 Gresham Street, London[1]
  • Telephone House, Birmingham[1]
  • Clifton Heights, Bristol[1]
  • India House, Glasgow[1]
  • Bridgewater House, Manchester[1]

The interior design of the studios was by the industrial designer Kenneth Grange.[4] Each studio had seating and microphones for five participants. Up to three sites could be connected at one time. Calls could be booked either by telephone or telex.[1]

The Confravision system was still in use in 1982.[5] A Confravision department was still listed in BT's internal directory in 1986.[6]

Development

The Confravision service developed from early experiments using microwave radio links between Post Office Telecommunication's headquarters in Gresham Street and the Post Office Research Station in Dollis Hill.[7]

Sound-in-sync digital audio transmission was used on some links where there could not be separate audio and video paths.[7]

Experimental services were launched in 1975 connecting Confravision to Sweden and the Netherlands.[1]

Following the early developments in Confravision, digital video compression techniques would substantially reduce the bandwidth needed for videoconferencing.[8] Experimental tests were made of transatlantic videoconferencing between the British Confravision system and AT&T's Picturephone service over a 1.544 Mbit/s T-carrier digital circuit running over the TAT-6 transatlantic analog submarine cable.[9]

References

  1. ^ a b c d e f g h "Post Office Telecommunications DLB 202" (PDF). www.samhallas.co.uk. July 1975. Archived from the original (PDF) on 2025-11-01. Retrieved 2026-01-17.
  2. ^ "Bridgewater House". www.engagingwithcommunications.com. Retrieved 2026-01-17.
  3. ^ "CW@50: How networking became the core of IT". ComputerWeekly.com. Retrieved 2026-01-17.
  4. ^ a b c Chung, Kokon (October 1971). "Conference Visionaries". Design Journal. Archived from the original on 2025-10-07. Retrieved 2026-01-17.
  5. ^ "Information Technology Year 1982" (PDF). Post Office Electrical Engineers Journal. 74. part 4 p. 351. January 1982.
  6. ^ Egan, Manus (1986), Egan, Manus (ed.), "British Telecom — Specialist Divisions", Communications: The Most Comprehensive Guide to the UK Telecommunications Industry, London: Macmillan Education UK, pp. 47–48, doi:10.1007/978-1-349-07816-5_14, ISBN 978-1-349-07816-5, retrieved 2026-01-19{{citation}}: CS1 maint: work parameter with ISBN (link)
  7. ^ a b Hayworth, J. E. (1972). "Confravision" (PDF). Post Office Electrical Engineers' Journal. 64. part 4, p. 202.
  8. ^ Parke, I. (1999), Sheppard, P. J.; Walker, G. R. (eds.), "The Evolution of Conferencing", Telepresence, Boston, MA: Springer US, pp. 14–25, doi:10.1007/978-1-4615-5291-8_2, ISBN 978-1-4615-5291-8, retrieved 2026-01-17{{citation}}: CS1 maint: work parameter with ISBN (link)
  9. ^ Cotton, Robert V.; Schaphorst, Richard A. (May 1983). "Study of potential standardization of video teleconferencing systems. Volume 1 – Final report, National Communication System Technical Information Bulletin 83-4" (PDF). apps.dtic.mil. Retrieved 2026-01-19.