News
At their November 11 meeting
Probus Club of Sarum welcomed Mr. Andrew Larkham
who gave a lecture about the development of telephony. His talk spanned from
Graham Bell calling his assistant Watson on March 10, 1876 to the present.
The first telephone book in the UK was issued on 15 January 1880. 1912 saw the
first public telephone exchange in UK. Growing numbers of switchboard operators
were needed for the expanding system.
Subscriber Trunk Dialling (STD) was introduced in 1958 to allow subscribers to
dial trunk calls without operator assistance. These had been mechanical and slow.
The invention of dual tone multi frequency was much faster (DTMF) and
superseded STD. This was soon followed by pulse code modulation (pcm), resulting
in the installation of Empress on 11/12/1961, the first pcm exchange in the UK
on a single pair of wires, which could carry up to 24 calls in parallel.
Despite these enormous changes over the years their was no let up in
development.This is now culminating in modern day fibre based broadband systems.
