GEC PX1211

GEC PRIVATE AUTOMATIC TELEPHONE EXCHANGES

P.A.X.

PX1211

This compact and completely self-contained telephone exchange provides secret automatic communication facilities for up to ten extensions. It is ideally suitable for small organisations, or as a separate auxiliary to the main telephone system in a large organisation. The single wall-mounting unit, finished in steel furniture green, incorporates all the automatic-switching equipment and an all-mains power unit.

The exchange has the following features:-

• Automatic connexion between extensions.

• Two-wire lines to each extension.

• One connecting link.

• Executive right-of-way for one extension.

• Operates from single-phase mains supply 50.60c/s, 100-110
  or 200-250 volts.

• Dial tone and ringing tone returned to a caller.

• Extensions numbered from 0 to 9.

• The exchange is suitable for operation in either tropical or
  temperate climate.

OPERATION
Any extension user is connected to any other extension by dialling a single digit. When the connecting link is free, an extension hears dialling tone on lifting his receiver, and ringing tone when the wanted extension is being called. If there is no tone when an extension lifts his receiver, the connecting link is engaged.

One extension connected to the exchange can have an executive right-of-way facility. This extension instrument is fitted with a pushbutton, and to break-in to an established connexion the extension user presses the pushbutton. If neither of the answering parties is the one required, they are requested to replace their handsets ; the executive then dials the required number. In this way the head of a small organisation, or the leader of a group in a larger organisation, can talk to any member of his organisation at all times.

LINES AND TELEPHONES
Each telephone can be connected to the exchange unit by any insulated twin conductor having a loop resistance of less than 300 ohms and a line leak greater than 130 000 ohms. This latter condition means that bare open-wire lines should - not be used with this exchange. An extension with executive right-of-way facility must be connected to the exchange by two insulated twin conductors.

Recommended telephones for this exchange are the 'New Gecophone' described in Catalogue Leaflet STL16 and the "G.E.C. 1000" Telephone and the G.E.C. Muraphone "K" described in Catalogue Leaflet STL13. When the executive right-of-way facility is required, the executive telephone must be fitted with a pushbutton. The ringing current is derived from the mains at 50 or 60c/s, compared with the normal telephone exchange ringing current of 25c/s, therefore slight adjustment of the bell is required to give the most satisfactory ring.

The connexions to extension lines are by screw-type terminals, and the only tool required to install the exchange is a screwdriver.

Each exchange is fitted with 10ft of 3-core flex to connect to the mains supply.

This compact, neat, inexpensive telephone exchange is easy to install, and available for quick delivery.
 

G.E.C. 15 LINE P.A.X.

GEC article on the PX1211

Last revised: August 01, 2025