Although the public network did not have DTMF (Touch-Tone) signalling until the arrival of digital exchanges, PABXs used this form of signalling from the 1970s. Tele 782 was an MF version of the 746. First introduced in 1979, this example from as late as 1985 features the later version of handset rest and earpiece used on 746s.
In many ways, this telephone is a dinosaur. Not only does it have the traditional innards of the 700 series phones, but the DTMF generator uses a circuit designed by Bell Labs in the late 1950s and generates the “one out of four twice” DTMF signals using just a single transistor but needing two precision tapped inductors. When this circuit was designed, transistors were expensive, but by 1985, plenty of phones were using multi-transistor chips instead of traditional phone components, such as inductors.
Since it was mainly used in offices, this model is most frequently found in the typical grey/brown livery of the period and as can be seen, the light has faded the grey except where stickers were attached at one time. Whilst not to the taste of many strict collectors, it is possible to buy a 782 with a modern replacement plastic body and in colours which would never have been used originally. However, I find it quite attractive.
