TELEPHONE No. 392

Combined Bakelite table telephone with DC trembler bell for use on extension plans in CBS No's 1, 2, 3 and Magneto exchange areas and on long lines in C.B. and Automatic exchange areas.

There is provision in the case for three buttons and the chassis will accept Keys No. 303A and 304A.

Also used on Private Wires.

Early models had a Filter, Suppression No. 6A fitted across the dial pulse springs.

This telephone had a tray for the subscribers personal directory but as from June 1940 the drawer tray was not fitted and instead the telephone was supplied with a Tray, Dummy, D62099 (a blank plate). This was probably a war time cost saving, as in late 1947 the tray was re-introduced.

This telephone used a battery of 3 volts to power the transmitter.

Available only in Black.

Mark 1 - has a Receiver, Inset No. 1L in the handset and switch bracket with plungers of the early type.
Mark 1A - has a Receiver, Inset No. 1L in the handset and switch bracket with plungers of an improved type.
Mark 2 - has a Receiver, Inset No. 2P in the handset and switch bracket with plungers of the early type.
Mark 2A - has a Receiver, Inset No. 2P in the handset and switch bracket with plungers of an improved design.

Telephone includes:-
1 x Bell No. 65A, Unmounted.
1 x Part No. 3/SCA/17, Black.
1 x Bell-gong No.2, Nickelled.
1 x Capacitor, M.C. No. 97.
1 x Telephone No. 164, Black.
1 x Coil, Induction No. 27.
1 x Tray, D 62076, Black or Tray, D1/62833, Black or Tray, Dummy, D62099, Black.
1 x Dial, Automatic, Dummy No.3, Black.
1 x Filter, Suppression No. 26A.

Supplied to the BPO by Ericsson, their Model N8444B - Circuit Diagram N54188 dated 1938.

Circuit diagram - N492 and SA 4091.

Diagram for Button labels - N620.

Drawing No. 63022 - Telephone components parts.
Drawing No. 63023 - Chassis components.
Drawing No. 63250 - Chassis components (improved switch hook buttons).
Drawing No. 90319 - Telephone parts (Mk 3A).
Drawing No. 90373 - Chassis components (improved switch hook buttons).
Drawing No. SBA12 - 300 type base plate.
Drawing No. SCA17 - 300 type complete case.
Drwaing No. SCA20 - 300 type case.
Drawing No. SCA47 - 300 type complete case (improved switch hook buttons).