NATIONAL TELEPHONE COMPANY
BATTERY INTERCOMMUNICATION TELEPHONES
Pattern No. B580
Comprises - Hand Combination Transmitter and Receiver, fitted with Ringing and Speaking Key, Cord, Bell and Line Selector.
An advantage in connection with these Sets is that a common battery of three or four cells provides the current required for both ringing and speaking.
The terminals are so arranged that the connections may be made on either back or front.
5 & 10 line models.
Was B77 in the 1903 catalogue and this pattern also catered for 15 and 20 line sets.
Last revised: July 07, 2020