TELEPHONE No. 254
|P.O. ENGINEERING DEPT.
Issue 2, 8.9.47
“TELEPHONE No. 254” PORTABLE TELEPHONE FOR 4-WIRE AND 2-WIRE WORKING
(a) 4-wire working. For terminating 4-wire private-wires with generator-signalling over the phantom or (using the telephone in conjunction with "Unit, Signalling, No. 6") for terminating 4-wire private wires with D. C. signalling.
(b) 2-wire working. For use on 2-wire circuits as follows:-
Stock provision of "Telephone No. 254” has not been arranged to cater for exchange areas requiring dials of S, B, or W type. If a "Dial, Auto., S. S. No. 10 LA" is not suitable, a "Dial, Auto. , S. S. No. 10…." for the area concerned should be requisitioned and fitted locally.
(c) 2-wire working, with battery, feed to line. For feeding transmitter current to line for C. B. or Auto. subscribers' instruments.
(a) The connexions are shown on Dgm. N 354; a copy of each of the three panels is fixed inside the lid.
(b) A "Key No.303A" (with three plungers), arranged as per Fig. 2, Panel 3, Dgm. N 4301, provides switching according to requirements.
(c) "Coils, Retardation, No. 3402" are arranged to give access to the phantom of the 4-wire circuit for signalling purposes.
5. Method of connecting the
Last revised: May 18, 2010