TELEPHONE No. 15

CBS TELEPHONE

Originally called the "Telephone, Wall, Intermediate with Magneto and Trembler Bells and Generator" it was later renamed as the Telephone No. 15 circa 1911.

It was a wooden wall intermediate telephone with switchable extension facility, used in CBS areas.  The phone can be secret or non-secret.

There was a Type 1 and a Type 2 with the Type 1 being the original "Telephone, Wall, Intermediate with Magneto and Trembler Bells and Generator" and the Type 2 is fitted with a detachable switch hook (G type or E type).  The Type 1 used a Bell, Receiver A and the Type 2 used a Bell, Receiver B, C or D.

An  additional receiver can be fitted to the terminals shown middle, right.

The top cover of the body is a writing shelf and has a paper clip attached to it.

For one exchange line and one extension with inter-communication.  Used as the intermediate station.

There is a switch for controlling the extension fitted on the flat panel, just below the magneto bells.

Complete with a generator, induction coil, relay, two bridging coils, trembler bell and magneto bell.

Fitted with Transmitter No. 6 on early types and Transmitter No. 2 on later variants.  The transmitter arm moved up and down.

Two batteries were housed in the lower part of the telephone and these were called Cells, 2-Block, Agglomerate, Complete.

Superseded by the Telephone No. 3 with Bellset No. 7.

Circuit diagram - CBS5, CBS6A and N115.

Found in the 1906, 1909, 1910, 1911, 1912, 1913 and 1915 Rate Books.

Telephone includes (1909, 1910, 1911 and 1913):-
1 x Bell No. 13A.
2 x Cords No. 116.
1 x Cord No. 222.
1 x Induction Coil 25/1 (1909) or Coil, Induction No. 1 (1910 onwards).
1 x Intermediate Switch.
1 x Relay E1 4000ohms (up to 1910) or Relay No 3A (1911 onwards).
1 x Generator No. 2 or Generator No. 4 (1913).
1 x Bracket, Generator, 3-terminal.
2 x Bridging coils 1000ohms.
1 x Condenser M.C. 1uf (1911 onwards).
1 x Transmitter "Ericsson" or Transmitter No. 2.
1 x Bell, Receiver A (Type 1) or Bell, Receiver B, C or D (Type 2) or Receiver, Bell No. 1 (1911 onwards).
1 x Magneto Bell.
1 x Trembler Bell.

Telephone includes (1915 and 1928):-
1 x Bell No. 14, unmounted, or No. 9A.
1 x Bell No. 15A, unmounted (early type), or No. 16A, unmounted (later type).
1 x Coil, Induction No. 1.
2 x Cords, Instrument No. 110.
1 x Cord, Instrument No. 222.
1 x Generator No. 2A or No. 4C.
1 x Hook, Receiver F.
1 x Relay No. 3A.
1 x Switch, Intermediate.
1 x Transmitter No. 2. (Earlier pattern had Transmitter No. 6).
1 x Condenser, M. C. No. 14.
1 x Receiver, Bell No. 2B for older type, or Receiver, Bell No. 1A for later types.

Frames, Notice, No. 2 and Labels No. 53, will not be maintained in these instruments. 

Last revised: February 19, 2026