TELEPHONES FOR NOISY SITUATIONS
Such as Aeroplanes, Engine Rooms, etc.
Fitted with Patent Throat Microphone Transmitter.
PATENT Nos. 136359/19 & 165288/20.
No. U 186 - Hand Combination Comprising our Standard Receiver, Throat Microphone Transmitter and four conductor flexible cord with ebonite handle and suspension ring.
No. U 187 - Hand Combination as above but with battery switch in the handle.
It frequently occurs in a telephone installation that there are one or two situations in which tile ordinary type of telephone is quite useless owing to surrounding noises. This is due to the fact that the ordinary microphone transmitters readily take up extraneous sounds and transmit them to the distant station, and at the same time reproduces them in tile receiver of the home station to such a degree that useful speech is impossible. This difficulty was experienced during the recent War when it became desirable to converse between the pilot and observer on aeroplanes, and between various parts of airships. The noise of the running engines was intense, and none of the standard microphones were of tile smallest use. To meet the difficulty, a special microphone was designed which is insensitive to air borne sounds. This is arranged to be placed on the throat in such a position that the throat vibrations agitate tile microphone contacts sufficiently to transmit speech, whilst surrounding noises have no effect. This phenomenon renders the throat microphone transmitter particularly useful in noisy positions such as Machine Shops, Stamping Mills, Engine Rooms, etc.
In order to make use of the Throat Microphone for tins purpose, we have designed the Hand Set shown by illustration U 86 which can be used on many of the standard telephones on which ordinary Hand Sets are at present used, provided it can be accommodated on tile existing switch hooks. In cases where this is not practicable, we shall be pleased to quote for complete instruments.
We shall also be pleased to quote to any special requirements calling for the use of the Throat Microphone.
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