PRIVATE OR PRIVATE BRANCH EXCHANGES
|N 308A||N 307A|
Designed for use as a private branch exchange, the N308A 50-line switchboard is similar to British Post Office type AT3796.
Drop type, hand-restored indicators, N4816D, are used for the exchange lines, and disc type, self-restoring indicators N4755M, for the extensions. Similar disc indicators N4752M in the keyboard give double negative supervision.
Exchange lines may be C.B. manual or auto, a dial being fitted for the latter.
Two keys "speak/ring" and "dial/ring-back" are provided for each cord circuit.
The board is matt polished and has a Bakelite micro-telephone with plug and jack connection also an "alnico" generator, a bell with cut-off key, and night extension keys.
Similar boards, N306A and N307A (illustrated) normally used as private exchanges, are
wired for exchange lines and have a common "dial/ring-back" key so that there is
only a speak/ring key per cord circuit.
|Code No.||Extension Lines||Exchange Lines||Cord Ccts||Dimensions ins||Weight lb|
|N306A||50||10 Wiring only||12||54 x 21 x 29||245|
|N307A||100||20 Wiring only||14||54 x 27 x 29||325|
|N308A||50||10||15||55 x 24 x 26||285|
Note - Partially equipped boards can be supplied, and type N308A with up to 15 exchange lines.
N308A was sold to the GPO as their Switchboard
Taken from the Ericsson Telephone Catalogue issue no. 49
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