Inside this 782RR MF telephone is a small circuit board bound in yellow shrink wrap,  This circuit is connected to the recall switch providing register recall instead of earth recall.  Register recall is better known as time break recall.  This works well on 50v lines but it does not work on some PABX's with lower voltages.   I assume that this is because BT PABX's were generally 50v, however it may be that the time break period is to quick to be recognised.

The 782 and the 8782 look identical, the difference being internal to the instrument.

The 782 was hardwired to the line with a 1000 ohm bell circuit in series with other bells on the same line and the recall would have been earth based,

The 8782 had a 4000 ohm bell circuit that was in parallel to other instruments and connection being by the current plug and socket arrangement. Earth and Time break models available, the time break from (1979).

782 & 8782

To the left we have a picture of the early version 782, you will notice that the dial plate is raised to accommodate the circuitry and the buttons are larger compared to the later version.

All models were available in two-tone grey and Ivory, although I have never seen the early version in ivory.

The 8782RR is fully compatable with BT’s  select services