Pattern No. B625
Comprises Granular Carbon Transmitter, Double Pole Receiver, Cord, Automatic Switch-hook, Induction Coil, Two-Magnet Generator, Bell, and Line Selector.
These instruments are intended for use where the stations between which intercommunication takes place are too far apart for Battery Ringing Sets further, they are cheaper to maintain than the latter. Pattern No. B625 is fitted with a mechanical click, which reduces the risk of making contact with two stations at once and is similar to pattern No. B630. Pattern No. B630, having a means of cutting the other lines off the circuit, allows of more privacy during conversation.
5, 10, 15, 20, 25 & 30 line models.