SIEMENS BROTHERS No. 310
From the SIEMENS BROTHERS & CO. LIMITED catalogue No.500/1954
Telephone No. Y45
The diagram below was found in a phone similar to the Telephone No. 310. This is probably a 310, with a plug ended lead, used by the British Armed Forces.
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 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 is in effect a BPO Telephone No. 232 permanently fixed to a Bellset 26 and came in black, brown, green and red. 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 310.
The 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 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 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 pattern of Bellset used on the 310 is different from that adopted by the British Post Office (Bellset 26); it is considerably smaller and half an inch shorter in height than the standard Bellset No. 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 162 directly above without external cordage between telephone and Bellset.
Last revised: July 27, 2021