Siemens Brothers Neophone 310, 311, 312 and 366
Novice collectors
are often baffled by these 200-type telephones with 300-series
numbers on the paster diagrams but thats because Siemens
Brothers (SB) had their own numbering system. The company named
all of them Neophones, although the British Post Office (BPO) favoured the circuitry
and shape of these instruments, only one pattern, the Type 310,
was adopted by the BPO. According to Siemens advertisements
at the time this was the worlds most efficient
telephone, Not only exceptionally handsome in
appearance and convenient to use but definitely superior to any
other telephone as regards speech transmission efficiency and
articulation.
Type 310
The Type
310 is in effect a BPO Telephone No. 232 permanently fixed to a
Bellset
26. Type 312 is a one-piece instrument with a larger case and
built-in ringer; the mouldings are also much sharper
than the rounded edges of the Type 310.
Click here for more
information on the 312.
Type 311
The Type 311 was the
matching wall instrument, compact and attractive but not adopted
officially by the BPO (it was very popular on the Southern
Railway and in Canada, however). The case design (but not the
circuitry) was also used by ATE (model T4127) and during World
War II a number of these phones were bought by the BPO for
providing emergency telephone service to bomb-damaged buildings
(the phones were small enough to fit inside a locked wall box).
It is unclear whether the BPO bought SB or ATE telephones. Its
ringer had the standard 1000-ohm impedance whereas the export
model Type 366 (made for Saskatchewans telephone system in
Canada) had 2000 ohms. Siemens wall Telephones Nos. 83 and 85
were similar but had older transmission circuitry.
Two patterns of
handset were fitted to the phones, one identical to the BPO
Telephone No. 164
design and another with a slotted cover instead of the normal
spit cup over the microphone. This slotted cover
occasionally turned up on BPO telephones, as Mouthpiece No.
18.
The telephone was supplied with
a dial for Automatic exchange systems of a dummy dial black for
C.B. systems.
The pattern of
Bellset used on the Type 310 is different from that adopted by
the British Post Office (Bellset No. 26); it is considerably smaller
and half an inch shorter in height than the standard Bellset 26.
It has a semi-circular terminal strip, a fairly standard bell
mechanism and slightly smaller gongs (two and a quarter inches in
diameter instead of two and a half inches). There is a No. 16A
Induction Coil with wooden coil cheeks and the base plate is
universal as it can be used for the table Bellset and the wall
phone Bellset, having two holes to line up with a wall bracket.
The table set has a light gauge pressed metal cover over the base
plate, with two large openings for vents which have a mesh
cover. On this plate is quite a large transfer with Siemens
Brothers & Co. Ltd. London and the relevant British and
Commonwealth Patent numbers. The Bakelite case of the Bellset is
also universal and does not have a cover as the standard Bellset
does; this open top enabled them to mount the equivalent of a GPO
Telephone No. 162
directly above without external cordage between telephone and Bellset.
Colours:
Black, Green and possibly others.
Users:
These
telephones saw widespread use on private systems installed
by Siemens Brothers Private Telephone Department, in a
number of countries abroad (particularly Saskatchewan in Canada,
the Bombay Telephone Company in India plus administrations
in Australia, New Zealand, Egypt, Southern Rhodesia and the Union
of South Africa) and on the former Southern Railway and British
Railways Southern Region. A number have been re-imported from
Canada for sale on the UK collectors market.
Further
information:
Engineering Supplement to the Siemens
Magazine, October 1931; Siemens Brothers Neophone Type 300, pamphlet
no. 509A, July 1932.
Note: The Siemens Brothers part
numbers are not the same as the GPO equivalent part numbers.
Click here for a spare parts picture
Circuit Diagram

Conversion to UK Plug and Socket
When removing the case - undo the two case
fixing screws and pull them towards you as far as they will go. The case then opens on the
hinge and the screws do not foul any components or wiring. When refitting
the case ensure the screws are still in the outward position.
-
Remove the white wire from the capacitor.
-
Connect the Red wire of the line cord to
terminal L2.
-
Connect the White wire of the line cord to
terminal L1.
-
Connect the Blue wire of the line cord to
terminal C.
-
Insulate the Green wire of the line cord
as it is not used.
-
Connect a 3.3k resistor between E and L1
terminals.
-
Connect a Rectifier Element No. 205 to the
red and green wires of the handset cord.
Wiring in directly
If you do not want to use a telephone line cord, but wish to wire the telephone directly into house wiring using telephone cable
(6 wire) then follow these instructions:
- Wire L1 to socket connector 5 using Orange/White of the cable.
- Wire L2 to socket connector 2 using Blue/White of the cable.
- Wire C to socket point 3 using White/Blue of the cable.
Additional Pictures
Model No. 311

Automatic variant


Automatic variant - internal view

Central Battery (CB) variant

CB Telephone - Internal view of front case

CB telephone - Internal view of bellset

View of telephone base
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