For use on existing magneto, c.b.s. or c.b. systems, this instrument is designed to save the expense of replacement when systems are modernised. It can be supplied with connections appropriate to any of the following conditions and is readily convertible to any other as required.
Stock instruments are in tropical finish and include a transistor generator, wiring for both a dial and a plug-in regulator, a 5000 ohm ringer and capacitors within the ringer and receiver circuits. A diagram is supplied with each instrument, indicating the various strapping adjustments and equipment requirements (where necessary) for conversions 1 to 10 above. Conversions do not affect the induction coil.
The Etelphone range combines high performance with attractive appearance and wide application. It includes the basic instrument designed in conjunction with the British Post Office and caters for the following requirements:-
All versions are similar in external design and available in a range of pleasing light-fast colours: black, ivory, concord blue, topaz yellow, lacquer red, two-tone green and two-tone grey. The instrument case and handset mouldings are of ABS copolymer, a high-impact material impervious to cosmetics, inks, oils and most chemicals. Table telephones are complete with a moulded desk connecting block in matching colour and both table and wall instruments feature a convenient off-hook position for the handset.
The transmission circuit ensures maximum frequency response and line sensitivity over exchange lines with loop resistances up to 1000 ohms. It employs a conventional hybrid transformer with a fixed balanced network and includes the following standard components:-
The dimensions are common to all versions of the Etelphone, being 11 in. x 9.25in. x 5.5in. (279 x 235 x 140mm); the weight varies between 3 and 4.6lb (1.3 and 2.1 kg).
|N2128H15T||-||Two tone grey|
|N2128H16T||-||Two tone green|
The N2208H is the wall variant.
Circuit Diagram for both models
Taken from the Plessey Telecommunications Publication No. 7099 (1/69)
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