|C.B., CORD, PRIVATE OR PRIVATE BRANCH EXCHANGE
These non-multiple lamp signalling switchboards may be equipped to operate as P.B.X.s connected to an auto., C.B. or magneto public exchange, or they may be used as private exchanges equipped as shown in the table below but wired for exchange lines, so that conversion for P.B.X. working can readily be effected at any time.
The casework is matt polished fine hardwood; the connecting wires are p.v.c. insulated, and the apparatus has tropical finish. Relays and battery feed retards are B.P.O. type "3000".
17-volt lamps are used. The supervisory lamps are mounted in the keyshelf, double positive supervision being given on local calls.
Relays for long extension lines are fitted when ordered; up to 5 on N371 and up to 10 on N372.
Wiring is provided for "ring back" keys and for a "coupling" key, but these are not equipped unless specified.
A ringing indicator and hand generator are supplied, also facilities for the application of power ringing.
A handset is usually provided for the operator, but a head-and-breast set can be substituted if preferred.
Cord test facilities and a night alarm bell and key are incorporated.
For P.B.X. working, separate double-ended through cords can be provided to connect auto. or C.B. exchange lines to selected extensions at night.
Cords are p.v.c. sheathed, nylon braided.
Orders for these boards should state the Type No., the numbers of circuits to be equipped and the particular requirements where variables are indicated.
Operating Voltage : 24 volts (nominal).
Busy Hour Current Drain for Fully Equipped Board: N371, 3.0A; N372, 4.0A.
Capacity and Wiring Equipment
Taken from the Ericsson catalogue, edition No. 55
Last revised: October 12, 2019