SIEMENS BROTHERS
NEOPHONE


Standard Neophone

neostd.gif (26488 bytes)Introduced in 1930 the Neophone was more or less the same model as the GPO Telephone No. 162 but nearly always came with the bellset attached.

Click for an article on the Original BPO Tele No. 162

See Siemens Brother No. 310

Microtelephone Subscriber's Set (GPO Telephone No. 162 Central Battery)

Central battery systems were less tolerant of the incidental variations in resistance of telephone transmitters which occurred when they were moved, and fixed„transmitter telephones were introduced to replace early handset telephones with the changeover to Central Battery and automatic working.  In about 1924 Messrs. Siemens Brothers of Woolwich, in conjunction with the Post Office, commenced research to overcome the defects in existing telephone handset transmitters. This research culminated in the production of the Transmitter No. 10.  To accommodate the new transmitter, an all moulded telephone was designed - the "Neophone".  It was originally moulded in black Bakelite but, shortly after its production, urea formaldehyde plastics became available, and it was moulded in that material.  Using pigmentation, the telephone was produced in red, green, ivory, and mottled brown.  The Neophone had no bell within its case and was originally used with a wall mounted bell set.  Later, bell cases were manufactured from the same materials as the telephones and could be fitted as a plinth to the base of the telephone.

Standard Black Telephone No. 162 Inside - note the transformer on the right
Metal cased Telephone No. 162 Inside view
Gold cased version Walnut finish - very rare

The Neophone was the first telephone to be made entirely in plastic.  It was adopted by the Post Office as one of its standard models and was also used by several overseas administrations.  Variations of the telephone were also made by other companies.

The receiver and new transmitter are assembled together in a moulded Bakelite handle to form a microtelephone (Telephone No. 164 ).  In the position of rest, the weight of the microtelephone presses down an horizontal bar extending between the two arms of the cradle; this causes the operation of the gravity switch accommodated in the base of the instrument.  As with the standard Central Battery table set, this telephone is designed to be interchangeable with similar instruments used on automatic systems, and the opening for the dial is covered by a dummy dial mounting which serves to hold the label and instruction card.

The telephone uses an inset transmitter, the No. 10 type, being employed.  The receiver is contained in an aluminium case, and the permanent magnet is a straight bar of steel.  The transmitter case is provided with a perforated metal cover, the holes in this cover being out of line with those in the base of the mouthpiece to prevent any object being pushed on to the diaphragm.  The plane of the opening of the mouthpiece makes an angle of approximately 45 degrees with the line of the handle.

The connections of the instrument, which is used in conjunction with a Bell Set No. 1.  The efficiency of the instrument is so high as compared with former instruments of the microtelephone type that it is necessary to provide means whereby the amount of the sidetone in the receiver, and the tendency of the instrument to "howl" by interaction between the receiver and the transmitter, are reduced.  This sidetone is also undesirable in that it causes the telephone user to lower his voice in an unnatural way.  Campbell in 1920 announced his invention of the A.S.T.I.C. (Anti Side Tone Induction coil).  This is effected by the small transformer (Transformer No. 35A) mounted in the base of the instrument.  One coil of the transformer is connected across the transmitter and the other across the receiver, and, in addition, the two coils are connected together on the "auto-transformer" principle.  The connections are such that the normal output from the transmitter to the receiver is opposed by the subsidiary output due to the transformer, thereby reducing the side tone to comfortable limits.

This microtelephone instrument can also be used on local battery systems.


neouniv.gif (37402 bytes)Universal Neophone

Introduced in 1934 the Universal Neophone had integral bells.

neophon1.jpg (38621 bytes)

 

 
 
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Last revised: May 16, 2017

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