‘New trunk phone circuit has widest bandwidth’
‘Oxford – Birmingham link’
50 years ago this was a headline from EW’s edition of February 1st 1961
The story opens:
‘A coaxial trunk telephone circuit with the widest bandwidth of any in the UK has recently been put into service by the GPO between Oxford and Birmingham.
‘The bandwidth extends from 312 kc/s to 12.34 Mc/s, and is capable of transmitting a TV programme with 625-line definition, together with 960 telephone circuits or alternatively 2,700 telephone circuits.’
‘Repeater stations are situated every three miles, and gain is automatically controlled to cover ageing or temperature changes in amplifiers.’
‘Power for the repeaters is fed along the coaxial cable as a cable 1000-0-1000 voltage; interlock arrangements give safe conditions for maintenance staff. Although power could be injected into any feeding point to serve up to 13 repeaters, it is actually fed from the terminal stations at oxford and Birmingham.’