PYE/TMC TELEPHONE No. T101 (1746 and 1746PB)


Desk Telephone 1746

Catalogue No. T101

The desk telephone Type 1746 is manufactured to meet the strin­gent requirements of the British Post Office 700 series of telephone instruments.
Finished in non-scratch ABS plastics, the '1746' is supplied in a wide range of non-fading colours including two-tone combinations.  Provision is made for fitting up to two keys and two lamps, to give facilities for shared service, exchange recall, priority, and main/extension calling when used in parallel.

The design incorporates printed wiring boards and the use of modern miniature components which provide utmost mechanical and electronic reliability.  Ease of servicing is ensured by the simple internal layout.

Dial pulse ratio of 2:1 or 1.6:1 is available.

Fully tropicalised versions are available, where all components are finished to better than BS.2011 Category 10/055/21 and the telephone meets the specification of Preece Cardew and Rider.

Alternative types
Apart from the normal direct line automatic instrument, versions with dial removed and a dummy dial substituted can be supplied for operation on central battery systems.

Other versions to supply the following facilities are available or can be produced from the basic instruments by use of conversion parts:-

  • Shared service line - automatic systems.
  • 2-wire PBX extensions with recall.
  • PMBX extensions with additional 'C' wire signalling.
  • PMBX operators' telephones.
  • Hotel telephones with 'message waiting' lamps and/or guest service symbols. (Cat. No. T105.) Press button and magneto versions are also available. (Cat. No. T150 and Cat. No. T103/4.)

Colours
Black, two-tone grey, ivory, two-tone green, blue, red. (In dual-coloured telephones the handsets and cords are in the darker tone.)

Accessories

  • Bell cut-off key Cat. No. A441.
  • Press-to-talk handset Catalogue No. A434.
  • Wall conversion kits Catalogue No. A481.
  • Handset retaining clip for use in maritime conditions and extra long line cords to special order.

Exterior
Case and handset moulded in ABS copolymer of acrylonitrile butadiene and styrene.

Cords
PVC-covered cadmium-tinsel con­ductor cords. Held in position by grommets which relieve conductors of any stresses.  Line Cord, straight: 3000mm. Handset cord, coiled: 250mm, uncoiled 1700 mm.

Cradle Switch
Sealed microswitch.

Dial
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: 10pps nominal.
Interdigit pause: 240m5 minimum Break-to-make ratio: 2 : 1 or 1.6 : 1.
Other ratios are available.
 

OVERALL TRANSMISSION CHARACTERISTICS
Transmitter

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 300-3400Hz.

Receiver
Rocking armature, replaceable capsule type.

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.

Ringer
Double coil, D.C. resistance 1000 ohms, impedance 2000 Ohms at 25Hz, 20Kg at 1000Hz.  Accepts ringing currents of between 16 and 30Hz. Bells, double gong, harmonizing tones.  An extension bell can be connected if required.

Dimensions/ Weight (unpacked)
Height - over handset 127mm
Width - over handset 237mm
Depth - 216mm
Weight - 1.5kg
 

Taken from Publicity Leaflet 2.5/A.A/3.78 (dated 1978)


Desk Telephone 1746PB (Push Button)

This push button telephone may be connected to any step-by-step office simply by transferring the wires from the existing dial telephone.  Use of the latest micro-electronic techniques including 4-phase MOST made possible the size, price, performance and reliability hitherto unobtainable.  Ample storage is provided (16 digits), for international dialing codes and DDD service.

Dial pulse speeds of 10, 16 or 20 PPS are available by a strapping option.  A unique collapse action of the push buttons reduces error rates.

The telephone is suitable for use on line loops with a resistance up to 1000 ohms.

Ringing current range 15 to 30 Hz.

Handset and case are moulded in a high grade ABS plastic. Standard colour is 2-tone fawn (grey).  Full colour range available with minimum quantity orders.

Unit is line powered with a self-contained nickel cadmium battery charged via telephone wire.

Can be operated in parallel with an ordinary dial set.


Taken from TMC Product profile (Canada)

 


 

 
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Last revised: February 04, 2019

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