STC TRIMPHONE PROTOTYPES
|These pictures are of an STC prototype Trimphone, which
is undated. This is a prototype of the
GPO Telephone No. 712 but is the number 66 the date, as the three hole
casing was superseded by a single case fixing in 1966.
The first trial versions of the Trimphone (1965) were all two-tone grey. The following year, two-tone blue, and green/brown were added.
The numbers on the base of the telephone below identify it as a Field Trial Trimphone:-
The numbers on the base are identified as follows:-
AAB - The first letter can be 'A' or 'G'. It gives the climate rating of the phone. 'A' is for UK use and 'G' is for tropical climates. The second letter may refer to the type of dial. The third letter is for the colour:-
A - Grey-white
Last revised: September 14, 2022