TELEPHONE No. 4

Standard CBS No. 1 table telephone if used with Bellset No. 5.
Standard CBS No's 2 & 3 table telephone if used with Bellset No. 15.

Fitted with Transmitter No. 2 and insert No. 3.  This transmitter could be rotated, to stop the carbon granules from packing.  Packing was a well known fault with fixed transmitters.

There was also a Telephone No. 4A. This had a plug ended 4 wire line cord instead of a screw type block terminal with six wire connecting cord.

This was the standard telephone instrument arranged for standing upon a table.  Since this telephone is simply a transmitter, a receiver, and a gravity switch, the instrument is not complete, and a separate  hand generator is provided, usually fixed to the desk or table in close proximity to the table telephone; the induction coil and magneto bell, with the condenser (should one be required), are fitted in a case and are known as a Bell Set.

The bell set for use with the telephone is Bell Set No. 5, if the condenser is not necessary, and Bell Set No. 15 if a condenser is required.  The bell set need not be fitted close to the telephone so long as it is within audible distance of it.  The primary battery is placed in a battery box and fitted close to the bell set to which it is connected.

Circuit diagram - N104.

See also the Telephone Efficiency Committees Report on Local Battery Area telephones.

Last revised: December 02, 2018