SWITCHBOARD No's N306 - N308

C.B. Switchboards


n308a.jpg (10389 bytes) n308a.jpg (10389 bytes)
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 AT3796.

Taken from the Ericsson Telephone Catalogue issue no. 49

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Last revised: October 12, 2019