|AUTOMATIC OR C.B. INTERMEDIATE AND EXTENSION
(BATTERY RINGING TYPE FOR INTERNAL WORKING)
These compact intermediate and extension telephones are designed for short lines, e.g., where the instruments are in one building and extra line wires can economically be provided for battery ringing.
Auto. sets with standard dial as illustrated, or C.B. sets with a dial dummy, are available. Components are of the highest grade, and wiring throughout is insulated with p.v.c.
A system may comprise an intermediate and either one or two extensions. In the latter case, the two extensions are in parallel, but provision is made for selective ringing. Signalling and local speech current is obtained from a 6-volt dry battery which is supplied only when ordered.
The following facilities are given:-
INTERMEDIATE can (a) call extension, (b) call exchange, (c) receive incoming exchange calls, (d) call extension with exchange held, (e) transfer an exchange call to extension. There is a through connection of exchange line to extension at all times, with incoming exchange calls answered by intermediate.
EXTENSION can (a) call or recall intermediate, (b) call exchange, (c) receive exchange signals, without switching at intermediate when the latter is unattended.
Intermediate-extension conversations cannot be overheard by exchange when exchange line is being held.
Extension-exchange conversations can be made secret or non-secret from intermediate, which has a star indicator to act as an "engaged" signal during such conversations.
Calls from extension ring a buzzer in the intermediate telephone. Calls from exchange are normally signalled at intermediate on an a.c. bell in a separate moulded case supplied with the instrument. The bell set is also used to terminate the line wires, and is connected to the telephone by a flexible cord.
The extension telephone contains a buzzer for signalling calls from intermediate, and an a.c. bell for receiving exchange signals, either when intermediate is unattended or when desired.
Note - P.V.C. insulated, nylon braided cords can be supplied if specified.
Black, Ivory and Forest Green colours were supplied. An Ivory and Black model was supplied to British rail.
Introduced around 1955.
Taken from the Ericsson Catalogue No. 55
The N1051A6T was supplied to British Railways.
Last revised: August 30, 2021