gec.gif (1164 bytes)GEC PABX 4+24/8+49

4+24/8+49 line
private automatic branch exchange

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.

Tie lines*

Normally up to 2 for 24 extension lines and up to 4 for 49 extension lines, on one route only.

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.

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.

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

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.
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.

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

Height    Width    Depth    Weight
4 + 24 line switching equipment PB2642    209 cm (82 in)    60 cm (24 in)    51 cm (20 in)    210 kg (460 lb)
8 + 49 line switching equipment PB2649    209 cm  (82 in)    120 cm  (47 in)    51 cm  (20 in)    420 kg (920 lb)
Switchboard    13cm  (5 in)    39 cm  (15 in)    31 cm  (12 in)    9 kg (19 lb)
A C mains unit SU3203 (4 + 24 line)    53 cm  (21 in)    39 cm  (15 in)    24 cm  (19 in)    28 kg (62 lb)
A C mains unit SU3204 (8 + 49 line)    122 cm  (48 in)    48cm  (19 in)    39 cm (15 in)    108 kg (238 lb)
Float charger SU4203    53 cm  (21 in)    39cm  (15 in)    24 cm  (9 in)    35 kg (76 lb)

*To be specified  when ordering


A Management Company of The General Electric Company Limited of England


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Last revised: November 30, 2021