TELEPHONE No. 28

A Local Battery handset with battery cut off switch fitted in the handle.  Being local battery it requires a battery power source at the telephone.

The handle is made of Ebonite with an integral switch.  The switch connects the telephones local battery into circuit, which then powers the transmitter.

Originally called the "Telephone, Micro" by the GPO.  The NTC "Micro Telephone, Hand, N.T. No. 5" was also renamed as the Telephone No. 28.  These types were superseded by the Telephone No. 86 in 1916.

This handset was used on many early telephones and could be fitted with a loop or hook suspension eye.  In these cases the handset was called the "Telephone, Micro, with loop suspension or the Telephone, Micro" with hook suspension" and a "Contact Hook" or "Suspender for Micro Telephones" would be fitted.

Hooks were discontinued in 1915 and only loop types were available.

Fitted with a Cord No. 403 (4 way), which was substituted with the Cord No. 421 in 1916.

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

Telephone Included (1910, 1911, 1912 and 1914):-
1 x Cord No. 403 or Cord No. 417 (Siemens Pattern Handset)
In 1914 the Telephone No. 28 description also included "Micro Telephones, Hand, N.T. No's 2 - 4) and the Siemens Pattern handset was discontinued, replaced by the "Transmitter Inset P.B." which was used on the Marks 234 and 235.

No. 28, with loop (1910 and 1911)
1 x Cord No. 403.
1 x Loop Suspension for Micro-Telephone.

No. 28, with Hook (1910 and 1911):-
1 x Cord No. 403.
1 x Hook Suspension for Micro-Telephone.

No. 28, with Hook and Cord No. 415 (1911):-
1 x Cord No. 415.
1 x Plug No. 401.
1 x Hook Suspension for Micro-Telephone.

No. 28A (1912):-
Formally called "Telephone, Micro, Glasgow Corporation Pattern without switch".

Telephone included (1946):-
1 x Telephone No. 28, with press switch.
1 x Connection, Mouthpiece No. 1.
1 x Diaphragm No. 12.
1 x Cord, Instrument No. 4/17A, Brown, 48" (earlier Mouthpiece No. 1 supplies fitted were with No. 4/03A, Brown, 48").
1 x Earpiece No. 14.
1 x Receiver 150 ohm.
1 x Transmitter, Inset No.3.

No. 28, with Loop, Telephone Suspension, No. 1 or No. 2 added. (No. 2 added for Mark 237 only) (1928 and 1946).
Used with:-
1 x Suspender, Microtelephone No.2.
1 x Hook, Receiver E or No. 12.

No. 28, with Loop and Cord 4/15A, Brown, 48" (1928 and 1946)
Used with:-
1 x Loop, Telephone Suspension, No. 1 added
1 x Cord, Instrument No. 4/15A, Brown, 48" substituted for Cord, Instrument No. 4/03A, Brown.
To be requisitioned separately - Plug No. 401.

No. 28A, without press switch - for Brighton and Glasgow only (1928).
1 x Connection, Mouthpiece No. 3 or 4.
1 x Diaphragm No. 23.
1 x Cord, Instrument No. 421 modified.
1 x Earpiece No. 12.

No. 28, with press switch (1928)
Refer to table below:-

Note: The Transmitter No. 10 includes a Mouthpiece No. 1 and a Transmitter-Inset No. 3.

Circuit diagram - N128.

Drawing - 8241 (Mark 4).

Mark 234

Receiver - Rear View

Receiver - Front view