gec.gif (1164 bytes)GEC
TEL/27D & TEL/31D


To meet the exacting demands of modern industry and commerce, G.E.C. invite you to study this simple, reliable and inexpensive telephone system that does not require an exchange.
At the single touch of a button, you are immediately connected to the required telephone you can have up to 11 or 21 telephones in your system. In the small business, it can provide all the internal communication necessary, while in the larger organization, it is an invaluable auxiliary to the main telephone system.


Simple Design
Stylish and elegantly simple, the telephone harmonizes with your modern office decor and fittings. A.B.S. plastic is used for the case and handset mouldings. It will not break it is very resistant to scratching, impervious to alkalis and acids and is easily cleaned with a damp cloth. There are no crevices or hollows where dust could be trapped. The overall attention paid to detail of design makes this telephone ideal for use in widely varying climates.
The press button switches are a proved design based on nearly sixty years experience in telephone engineering. The design prevents dirt from becoming embedded in the contacts.
The operating button incorporates a label protected by a clear clip-on plastic cover.
The handset is a special lightweight design and has the same high-efficiency performance as those supplied to Telephone Administrations throughout the world.

Simple to Use
Lift the handset and press the appropriate button instantly a buzzer sounds at the called telephone and continues as long as pressure is maintained.
Release the finger pressure to silence the calling buzzer the button remains depressed to maintain the speech circuit.
Replace the handset at the end of the conversation to release the speech circuit the button is automatically released in readiness for the next call.
When a call is received, lift the handset to complete the connexion.

Simple to Install
You only have to install a multi-core cable "highway" around the offices and workshops that need the intercommunication service; the telephones are simply wired into the "highway".
You can start in a small way with only a few telephones and add telephones as required up to the maximum of 11 or 21; additional telephones do not effect the wiring of an existing circuit.
The length of interconnecting cable between the two most remote telephones can be as long as 360 metres (400 yards).
To operate the system all you need is either a G.E.C. mains supply unit or dry batteries.

Loudspeaking Executive Telephones
There is also a press button intercom system which includes up to three loudspeaking executive telephones. When using one of these units, you dominate the system ; you can call any extension, whether or not engaged, and can exercise complete priority. In addition, you have complete freedom to move around your office or make notes and consult references during a conversation.

Full information on this unit is given in our leaflet reference number ITL3.

Catalogue Number
10-line telephone: TEL31D
20-line telephone: TEL27D

Moulded in dual-grey A.B.S. high-impact plastic.

PVC-covered, grey. Cadmium-tinsel conductors. Held in position by grommets which relieve conductors of any stresses.
Line cord, straight, 183 cm ( 72 in)
Handset cord, coiled, 25 cm (10 in) unextended, 170 cm (68 in) extended.

Microphone : carbon-granule replaceable capsule type.
Sensitivity, +30 dB relative to 1 mV/dyne/cm2 at 20 dyne/cm2 input.
Receiver : rocking armature, replaceable capsule type.
Sensitivity, +46 dB relative to 1 dyne/cm2/

Maximum Cable Length
360 metres (400 yds)

Telephones per System
11 or 21 maximum, depending on telephone.

Power Supply
6 V d.c. (1.5V for speech, 4.5V for calling). Either G.E.C. mains supply unit type SU1301 or dry batteries. When total cable length is less than 137 metres (150 yd), single 6-volt supply at mid point of system is adequate. For longer cable lengths, two 6-volt supplies should be used, equispaced along the cable.

Single coil, d.c. resistance 30 ohms; operates from the 4.5volt d.c. supply.

Conference Calls
Up to 6 extensions can be connected into a common circuit at any one time.

Suitable for use in all climates.

Complete telephone: 2.3 kg (5 lb).
Handset: 280gm (10 oz).

Taken from the Catalogue Leaflet No. ITL 5B 

BACK Home page GEC Main Menu Search the Site Glossary of Telecom Terminology GEC Telephone Quick Find All Telephone Systems

Last revised: January 30, 2021