Siemens Brothers Neophone 312
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 their 200 style telephones: Neophones.
The Type 312 is a one-piece instrument with a larger case
than the Siemens 300 style telephone and
built-in ringer. The case mouldings are also much sharper
than the rounded edges of the 310.
The Type 312 is also known as the Universal
Neophone.
The
handset was identical to the BPO No. 164
design with the normal ‘spit cup’ over the microphone.
Colours:
Black, brown, walnut 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.
Further
information:
Engineering Supplement to the Siemens
Magazine, October 1931; Siemens Brothers Neophone Type 300,
pamphlet no. 509A, July 1932, held in the BT Museum, London.
Converting to UK Plug and Socket system
Parts List for 312
312 Paster Diagram
Conversion to UK Plug and Socket
To wire a Type 312 to the UK telephone socket system follow these instructions. It is illegal to connect unapproved apparatus to
any public network.
- Remove existing line cord (if fitted).
- The Bellset should remain wired to the phone as per the 312 diagram.
- Remove one wire from the capacitor (square grey box on the bellset) and
insulate.
- Remove any wire link found between L1 and E.
- Insert 3.3k resistor between Bellset L1 and E.
- Terminate the white wire of the line cord on Bellset L1.
- Terminate the blue wire of the line cord on Bellset C.
- Terminate the red wire of the line cord on Bellset L2.
- Insulate the green wire of the line cord.
- Connect the rectifier element across telephone terminals 5 and 6.
If you wish to use the telephone without the bell - because old mechanical ringers can sometimes cause problems - then leave out the
resistor and wire strap.
It may also be desirable to also modify the telephone as recommended in the section on
how
the convert to PST.
Additional Pictures
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