GEC PABX 4+24/8+49

STANDARD FEATURES
Maximum capacity
4 public-exchange lines and 24 extension lines; can be extended to 8 public exchange lines and 49 extension lines.

Connect circuits
Provision for 4 simultaneous inter-extension calls for 24 extension lines, and 8 for 49 extension lines, in addition to a maximum of 4 or 8 public-exchange calls.

Numbering scheme
Within the range 21 to 69 for extensions; 7 for tie-line access; 8 for night service; 9 for public-exchange access; 0 for operator-switchboard access.

Public exchange service
Outgoing: direct access from extensions, or through operator's switchboard.  Individual extensions can be prevented from dialling public-exchange calls.
Incoming: through operator's switchboard.

Enquiry and transfer
Telephones with a pushbutton can be supplied* to all or selected extensions to enable a public exchange call to be held while the user calls another extension with an enquiry.  When the enquiry is complete, the original extension returns to the public-exchange call, or can transfer it to another extension or to the operator.

Night service
Incoming public-exchange calls can be answered from any extension by dialling '8'; alternatively, the feature can be restricted to one extension only*.  Calls can then be transferred to other extensions by the enquiry and transfer method.

Trunk offer
The operator can offer a public-exchange call to an extension already engaged.

OPTIONAL FEATURES

Conference*
Designated extensions can be connected together via a special circuit.

Fire alarm*
Various procedures are available to suit individual requirements and local fire regulations.

Staff location*
Staff absent from their offices may be called by dialling a special locating number and a personal code, to operate lamps or bells.

Secretary service*
A secretarial switching telephone enables secretaries to filter calls to an executive.

Manual extensions*
Up to 4 telephones without dials may be wired direct to the operator's switchboard for special priority services.

Route restriction*
Individual extensions may be permitted to dial local but not long-distance calls.

Mains-fail protection
Public exchange lines can be automatically connected to designated extensions in the event of an AC mains supply failure.

GENERAL
Mode of operation
Fully automatic operation using 2-motion selectors, uniselectors and relays.  All conversations secret from each other.

Tones and ringing
All-electronic tone generator provides dial tone, ring tone and current, busy tone, number-unobtainable tone and operator intrusion tone.

Signalling
Required dial-pulse characteristics: 7 to 14 i.p.s., 2:1 break to make ratio.

Alarms
Lamp indication at switchboard.
Urgent: release alarm, ring fail and blown fuse.
Deferred: failure to replace receiver (PG condition).

Power unit*
AC power unit: input, 100 to 120V or 200 to 250V 50 to 60 Hz single phase; 50V d.c., output 5A for 4 + 24 line, 10A for 8 + 49 line.
or
Battery: 50V 32AH ; with float charger, input as for AC power unit, 50V d.c., output 3A.

Line-loop resistance
Not to exceed 900 ohms.

Construction
Switching equipment: Plug-in and wired-in units on a steel framework in a floor-mounting steel cabinet (painted grey) with lift-off dust-proof panels front and rear.
Switchboard: dual grey desk-mounting console.

Dimensions and weight

*To be specified  when ordering

1968

GEC-AEI TELECOMMUNICATIONS LIMITED
A Management Company of The General Electric Company Limited of England

Last revised: August 01, 2025