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| Click here for a general description of the Gecophone Circuit diagrams and how to convert to Plug and Socket In 1955 GEC decided to renumber all their telephones and to start with the prefix
TEL. The ST13xxx, ST14XX, ST15xx, ST16xx, ST17xx and ST18xx series, which was the part number
range (from 1946) for the
this series of phones, were part of this renumbering. Please see the table below for more
information. Prior to 1946 these telephones were identified by numbers
only. GEC GECOPHONE A table telephone of distinctive appearance, supplied in three models one for use with automatic exchanges, one for use with manually operated central-battery systems, and the Convertible Gecophone, which can be used with magneto, C.B.S. manual, C.B. manual or automatic systems and can easily be converted from any system to any other with the minimum of trouble. The instruments can be supplied with a neat metal bracket for wall mounting; the line wires are then brought straight to the instrument, the terminal strip and connecting cord being unnecessary.
The Gecophone is a self-contained telephone which has proved its qualities under hardest service conditions. All components are mounted within the moulded bakelite case, yet every part is accessible. The induction coil,
cradle switch springset and dial are mounted in the case, which has entry for the handset cord close to the connecting strip the line cord enters through a plastic collar attached to the baseplate, on which the bell and capacitor are mounted, and this complete unit can be separated from the case very easily, exposing all parts. The shape of the case is such that the instrument can easily be lifted and carried by one hand. The cradle, with its four short prongs of equal length, combines a robust design with a neat appearance. The cradle-switch mechanism has been specially designed to eliminate a tendency to stick. Twin contacts ensure maximum reliability. The handset is fitted with an inset type transmitter. The flexible handset cord gives exceedingly long service; the conductors are made from tinsel that withstands 200,000 reciprocations without fracture. The G.E.C. Trigger dial, adopted by the British Post Office as their standard, is fitted with a stainless steel finger plate which retains its high polish indefinitely. The four-way Bakelite terminal strip, connecting the line wires to the telephone cord, has moulded separators to provide long leakage paths between terminals. There are separate entrances for line wires and cord. Facilities are provided for the operation of two telephones in parallel without bell tinkling during dialling. The transmitter and receiver are British Post Office standards, and the high efficiency speech circuit gives maximum volume with uniform frequency response and excellent sidetone suppression. The unfailing efficiency of the G.E.C. trigger dial mechanism (British Post Office Standard) is well known, and a special spark-quenching circuit protects the impulsing contacts during dialling. If required, a suppression circuit can be fitted to prevent interference with nearby radio receivers during dialling.
Ventilation holes in the base (pictured above) and beneath the specially designed cradle permit a circulation of air through the instrument to minimise internal condensation.
The cradle-switch springset has large insulators to ensure long leakage paths between springs. Flexible cord conductors are V.I.R. covered and braided overall. Since textile bindings are not in contact with conductors, moisture absorption cannot cause leakage. Metal parts are specially finished and all wiring is specially made to resist the effects of high humidity and salt-laden atmospheres. All coils are specially treated to render them impervious to damp, heat and sudden changes of temperature. For very dusty atmospheres, a transparent plastic cover can be fitted to the back of the dial to give complete enclosure to the mechanism. Ships’ telephones are normally ivory in colour with cords finished to match and are fitted with an A.C. buzzer in place of the usual bell. A multi-way plug may be fitted in place of the terminal strip, if required. Standard pattern Gecophones are supplied in black only. Tropical pattern Gecophones are normally black, but can be supplied in ivory, jade green or Chinese red with cords and terminal strips finished to match. For ordering please quote the colour required after the Catalogue Number. A magneto extension bell in the G.E.C. Catalogue No. BE1100 series (Standard) or BE1200 series (Tropical), is recommended for use with the Gecophone, to provide calling signals at a distant point, indoors or out, or to augment calling signals in very noisy surroundings. GECOPHONE CATALOGUE NUMBERS
* Note:- For use with the 10-line All Relay P.A.X., Cat. No.
PX1110 (Standard) and
PX1210 (Tropical). CONVERTIBLE GECOPHONE CATALOGUE NUMBERS
Convertible Gecophones arranged for Magneto working each require a 3-volt battery. G.E.C. Dry Cells, Catalogue No. BA4955, are particularly suitable for this purpose and are suitable for service in either temperate or tropical climates. Weight Diagrams ADDITIONAL PICTURES
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GEC
G.E.C. telephones for service in tropical climates incorporate various special features, which are the result of long experience. A shunt may be connected across the transmitter to minimise the minute arcing that tends to occur at the
granules and electrodes as the cradle switch operates the accelerated tendency towards frying often shown by transmitters in the tropics is thereby offset. The effect of any increase in transmitter resistance upon line circuit conditions is also minimised by the shunt. The loss in volume efficiency is very small and is partly cancelled by reduction of sidetone, the
net result being a difference of only 1db. When required the shunt is connected by the simple transfer of one wire from one terminal to
another.
All apertures are protected against the ingress of insects. The special cradle (shown cut away to reveal the ventilation holes) has four short prongs which securely hold the handset and withstand rough handling.
