BATTERY INTERCOMMUNICATION TELEPHONES
Pattern No. B470
Comprises Granular Carbon Transmitter, Double Pole Receiver, Cord, Automatic Switch-hook, Induction Coil, Bell, Push Button, and Line Selector.
One of the special advantages in connection with this type of instrument is, that it has provision for connecting an additional switch, so that by the aid of same, and some additional wiring, two, or more, particular stations so fitted can speak together privately, without the possibility of any third person being able to overhear the conversation.
5, 10, 15, 20, 25 & 30 line models.