GTD 1000

PXML No. 59
APPROVAL No. NS/2164/3/E/0226B4/C and NS/2164/3/G/451995

The GTD 1000(E) is a stored program control (SPC) PABX employing PCM network and switching techniques. It is a modular system using two types of equipment cabinet. One cabinet for the common equipment (CEC) and a maximum of four peripheral equipment (PEC) cabinets. An optional second CEC may be added to give Duplex (redundant) common control. An auxiliary equipment cabinet (AEC) can be provided which accommodates the TJF and any additional interface circuits.
Depending on the system configuration the maximum capacities are:- 64 trunks and 1024 stations or 256 trunks and 640 stations with 8 attendant consoles. This allows for 192 simultaneous calls.

The system is normally powered by a Harmer & Simmons rectifier (TClA range). Standby power can be provided to sustain the load of the whole system for a nominal 7 hours.

The GTD 1000 was superseded by the Omni range of Atea switches.


(FERRANTI Responsibilities have now been assumed by GPT Communications LTD, Wellingborough, Northants)

The system is fully approved and given approval numbers; NS/2164/3/E/0226B4/C and with NS/2164/3/G/451995 added for private maintenance of DDI sites. The current issue of PXML 59,(Issue B) gives details on the latest software and hardware approved. There are two distinct sets of hardware used on the system. HARDWARE A is used on systems initially installed with SVPR and updated to SVPR, HARDWARE B is used on systems initially installed with SVPR, and The two hardware sets comprises common items, as shown in the PXML. Software is stored on cartridge tape.

All new systems being installed with use software releases SVPR, or

NOTE: Only systems installed with SVPR 4.1.3.lA, or SVPR, software are approved for the PRIVATE MAINTENANCE of DDI sites.

The software release can be verified by the label on the backup tape or on the header, after entering the maintenance (level 3) partition. The level 3 partition is the maintenance level. Access is gained using the teletype or keyboard/VDU type and keying:-

           KEY:                     RESPONSE:
           SL (space)
           OL (full stop)           ?
           YYY (full stop)          SECURITY CODE?
           XXXXXX (full stop)       ** SL OL EO Level 3
                                    (The lock is now open)
           RC (full stop)

(The header showing the software release is printed)
Note: YYY - Ferranti allocated code (usually CEPT or the software SVPR number).


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Last revised: November 05, 2021