Automatic Metal-clad Telephone
Flush or bulkhead mounting type

Catalogue No. T108

The Pye TMC automatic metal clad telephone has been designed for installation as either a flush mounted or bulkhead unit.

The ruggedly constructed case and deck are manufactured from sheet steel. The deck which is hinged along the bottom edge, is retained by a single captive screw, it can therefore, be swung open for maintenance purposes. The finish is hammer tone grey stoved enamel.

Standard '1746' telephone components are used throughout. The handset and its cord are black and held firmly in place by a retaining device. The robust nature of this instrument makes it particularly useful for industrial and shipboard use.

A version can be supplied with recall/earth/priority button.
Dimensions/Weight (unpacked)
Height - 158 mm
Width - 310 mm
Depth - 110 mm
Weight - 3.5 Kg

Pye TMC Stock No S538270 or S538271 (with recall/earth/priority button)

Technical Data

The case and deck is fabricated from sheet steel and finished in hammer tone grey stoved enamel.  The hinged deck can be swung open for maintenance purposes.  The handset is retained on the deck by a plastics covered clip ensuring retention under severe conditions of vibration.

The complete construction is very robust and suitable for use in arduous conditions.

PVC - covered cadmium-tinsel-conductor cords.  Held in position by grommets which relieve conductors of any stresses.  Handset cord, coiled: 250 mm uncoiled 1.7 m.

Cradle Switch
Sealed microswitch.

Articulated-trigger type with self-compensating action.  Projects through self-centering ring on case.  Characters printed black on silver background beneath clear plastics finger plate.
Speed: 10 pps nominal.
Interdigit pause: 240 ms min
Break-to-make ratio: 2:1

Overall Transmission Characteristics
Carbon granule replaceable capsule type.  The change in sensitivity over the input range 3-30 dynes per sq. cm. is less than 5db at a given frequency in the range 300-3400 Hz.

Rocking armature, replaceable capsule type.  The receiver has a mean sensitivity of +46 2dB relative to 1 dyne per sq. cm. per mW of available power when tested with an artificial ear.

Automatic Regulator
An automatic regulator is fitted to limit speech-signal amplitudes on lines shorter than 400 ohms: introduces virtually no attenuation on longer lines.

Double coil, d.c. resistance 1000 ohm; impedance 2000 ohm at 25 Hz, 20 K ohms at 1000 Hz.  Accepts ringing currents of between 16 and 30 Hz. Bells, double gong, harmonizing tones. Extension bell can be connected if required.

Suitable for use in all temperate climates. Tropical instruments available to order.

Taken from Publicity Leaflet T108/3/74 (dated 1974)

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Last revised: February 04, 2019