NTX 30M & NTX 30

PXML No. 125
APPROVAL No. NS/2164/23/G/452433 (NTX30M) and NS/2164/23/G/452431

Made by Atea of Belgian and distributed in the UK by Ferranti GTE Ltd, then Ferranti Business Communications, then Siemens, then GPT, then Siemens Gec Communication Systems Ltd and finally Siemens.  The system is known as the Omni S1 and S1S and was sold by Norton Telecom/GPT/Siemens as the NTX30 (pictured at the back) and NTX30M (pictured to the right with the telephone on top).  The NTX30, NTX30M and S3 systems have now been superseded by the Omni 200 range.

The PABX's (Private Automatic Branch Exchange) are Electronic, Digital, Stored Program Controlled (SPC) employing Time Division Multiplexing (TDM) to establish connections and Pulse Code Modulation (PCM) for local voice transmission.

The standard attendant equipment comprises an attendant (operator's) console, an attendant interface card (ATTI2) and an extension line card (SLUK). These cards are located in the Peripheral Equipment Modules (PEM's).

The Omni supported numerous type of attendant consoles. Early systems used a console called a Pacet (looked like a slug with a red LCD - shown to the lower left in the picture to the right).  Norton Telecoms marketed a screen based console called the Level 1. This was simple and was later developed into a directory and call logging screen based console called the Level 2.  Level 2 consoles used a smart card for backing up directory and call logging set-up.  The Level 3 console appeared in the early nineties and this was an enhanced Level 2 with a Disc Operating System and greater on board memory.  The Level 3 console used floppy discs as a backup media for set-up, directory and call logging records.

A Busy Lamp Display Unit (BLDU) can also be provided on the Pacet only, as a separate unit, which fits on top of the console.

The PABX is designed such that a data option (D2) can be integrated into the system, to provide voice and data processing which are separated completely by using individual buses.

In the event of a power or major equipment failure predetermined extensions are connected to the Public Network.  Since the extension instruments normally use time break recall and the exchange lines are normally earth calling these extensions will not be able to make outgoing public exchange calls in the by-pass emergency switching mode unless they are provided with earth recall telephones.

In the case of systems fitted with DDI lines these can be connected to a call answering machine in the by-pass emergency mode.

Introduced mid 1985 on an interim basis. The system was approved late 1996 under PXML No 109 (now PXML No 125) and approval number NS/2164/23/G/452431. The system comprises a single cabinet, operator's console(s) and test jack frame (TJF), to which the cables from the PABX are terminated.

The picture to the right shows a Omni S1.  This is an early version with a cartridge tape drive (lower centre).  This was replaced later with a 5.25" floppy disk device.

The cabinet contains three files (shelf assemblies) for housing printed wiring cards:-

Power Supply Control file (10 slots)

Get Started file comprising a Common Equipment Module (CEM with 15 slots) plus a Peripheral Equipment Module (PEM0 with 21 slots). Early systems had quarter inch tape drives that were superseded by five and a quarter inch floppy disc drives.

An Expansion file which is a second Peripheral Equipment Module (PEM 1 with 36 slots).

Each PEM houses control cards and interface cards for extensions and trunks.

The maximum (PEM 0 + PEM 1) capacity for each item listed is:-
328 extensions
92 trunks (exchange lines, DDI and private circuits) in 32 trunk groups.
1 - Private digital link (32 channel CEPT span)
4 - Operator's consoles
16 - DTMF receivers
2 - 8 party conference circuits
2 - serial data circuits (TTY, VDU, Call logger etc)*
16 - MFC receivers
8 - Dial Tone Detectors
64 - Data lines

For systems with only the GET STARTED (PEM0) configuration, the maximum number of extensions is 144 and 36 trunks.

The above are the theoretical maximums for each Item assuming the other items are provided at some reduced level or not at all. The practical maximums will vary depending upon specific customer requirements.

Get Started (PEM0)

Extension Trunks DTMF Receivers Consoles
96 8 4 1
80 12 4 1
64 16 4 1

Expansion (PEM1)

Extension Trunks DTMF Receivers Consoles
152 12 4 0
136 20 4 0
112 24 4 1

Total (PEM0 + PEM1)

Extension Trunks DTMF Receivers Consoles
248 20 8 1
232 28 8 1
176 40 8 2

Introduced mid 1986 and approved late 1986 under PXML No 111 (now PXML No 125), approval No NS/2164/23/G/452433. The system comprises a single PABX cabinet, test jack frame (TJF) and optional operator's console for a system fitted with an integral AC power supply. A second cabinet is normally required for a system fitted with a DC/DC converter.

The PABX cabinet contains a power block, ringing generator and a shelf assembly with 36 card slots to house printed wiring cards. In addition, a floppy disk unit, a magnetic disk drive and battery pack can be provided as required.

The maximum capacity for each item listed is:-

     168 Extensions with the 8 circuit line card

     256 Extensions with the 16 circuit line card

     44 Trunks (exchange lines, DDI and private circuits) In 64
     trunk groups.

     2 Operator's Consoles

     8 DTMF Receivers

     2 - 8 Party Conference Circuits

     2 Serial Data Circuits (TTY, VDU, Call Logger etc)

     8 MFC Receivers

     4 Dial Tone Detectors

     44 Data Lines

The above are the theoretical maximums for each item assuming the other items are provided at a reduced level or not at all.
The practical maximums will vary depending upon specific customer requirements.

Practical Configurations:

4 DTMF Receivers, 1 Console, 1 Tone Detector and 12 Alarm Relays

8/96; 12/80; 16/64 - 8 cct line card
8/192; l6/160; 16/128 - 16 cct line card

By connecting a V24 Splitter, then more than 2 devices can be connected up to a maximum of 4, to any of the systems.

Technical Information


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Last revised: September 25, 2021