In the 1970s, the 700 Type telephone was given a minor facelift. The body shape was slightly modified as was the method of fixing the case to the body. Later on, the cradle rest was further modified to ensure that the handset sat firmly on the hook-switch. Other improvements were made to the component mounting inside the phone. This design remained the basis for the Post Office’s first commercial forays into keypad telephones, initially with loop disconnect pulsing, but latterly DTMF versions for PABX use emerged.
The 746 remained available from BT even after the 1981 liberalisation. It was re-engineered with a 4K ohm bell for modern plug & socket working and was re-branded the Yeoman.
The keyphone variants of the 746 went through several stages. Initially, the keypad was battery powered and where possible this was recharged from the line while on-hook, though not all exchange types allowed this (eg Tele 764). Later, the units were line powered, such as Tele 756. The shape of the keypad keys also varied between oblong and square. These models were always described as ‘Self-contained’ (SC) since external repertory diallers had been available for some years.
Change in body shape
As mentioned above, the body was redesigned to provide a more positive seating for the handset. These images show the two variants.