APPROVAL No. NS/1043/23/G/452425

The MCX was made by Siemens and was also known as the EMS 601. It was introduced into the UK by a company called Norton Telecoms around 1986.
The switch was sold world-wide and is still made and supported by the Brazilian arm of Siemens. The system can be built up from scratch and any PCB can be programmed on site.  The MCX was once given the brand name 'Royale' when it looked likely that BT was going to take the product on board around 1985.

The system can be powered from ac mains or from a dc supply, the latter can be from a floating-battery system or battery eliminator.
The software is contained in solid-state semiconductor memory with backup on a double sided floppy disk. The common control, central processor and disk drives can be duplicated (two cabinets needed) to provide active and standby units. The system is non blocking and employs pulse code modulation and time division multiplexing to switch voice data between calling and called parties, it can service up to 992 ports. These ports can be occupied by lines, trunks and code receivers.

Each system offers a wide choice of features and facilities for all system sizes, these include direct dialling in, operators consoles, blind operators consoles, analogue and digital telephones (Digite 216, 260 and 452) and an interface for digital communication equipment. A fully equipped system is contained in two integrated cabinets. An integrated TJF and Power Supply cabinet (MAC) was also made available on all but the earliest systems. The equipment is modular in construction facilitating expansion and reconfiguration, three different cabinet sizes are available. A modem can be connected to allow remote maintenance, diagnosis and programming functions to be performed. In the event of a mains power failure emergency switching of exchange lines is provided.

The system will also support ACD working and RADs.  Agent telephones are by means of the Digite 452, 260 and 216.

The MCX can handle up to 1024 ports in a twin cabinet configuration (shown above, with the third cabinet being a MAC), where 992 ports are customer assignable. The design capacity is 800 lines with 104 trunks, 16 code receivers and 8 attendant consoles.

The 104 trunk lines can be split in any ratio between exchange lines, DDI or inter PBX circuits.

The customer assignable ports can be used for analogue or digital circuits with maximum of 400 digital extensions, 992 analogue circuits or any combination thereof.

The system can operate with a one, two, three, or four digit station numbering plan. Trunk groups are accessed also by a one, two, three, or four-digit access code.

The system access codes are totally flexible

The equipment is designed to operate within a temperature range of 40 to 400C and a Relative Humidity of 1% to 90%.

The system has a maximum of 32 classes of service. Each class of service can be arranged in customer memory to allow or deny access to many combinations of system features. Any one of the 32 classes-of-service codes is stored in customer memory for each station and can be changed at any time to another class-of-service code that either allows access to additional features or denies access to existing features.

Digite 260 Digite 452

Tone Channels 31 available
RS 232 (V24) 1/0 Ports - 2 per system
Floppy Disk Drives - 2 per EMS601 cabinets (8in on early software & 3in on latter)
8 Port Conference Circuits - 8 (4 per module)
Port Conference Circuits - 48 (24 per module)
Assignable Ports - 992
Receivers - 32 (4 per shelf)
Digital Ports - 400
PCM 30 (Megastream) Ports - 8
DASS 2/DPNSS - 8 (30 channel cards)

System Features Related Capacities:
Station Message Detail Recording
SMDR Active Call Buffers - 224
SMDR Call Record Transit Buffers - 12
SMDR Formatted Output Buffers - 12
Account Codes
Length 1 - 11 digits
Assigned - 255

Traffic Metering Registers/Counters 255 (2 byte)

Authorisation Codes
Direct Inward System Access 16 (2-4 digits)
Restricted Station Access 16 (2-4 digits)

Night Service
Zoned Universal Night Answer (ZUNA) - 4 Zones
Assigned Night Answer (ANA)
(Trunk to Station Assignments) 224
Special Night Answer Position (SNAP) 1 Station or Hunt Group per System

Attendant Console Related Capacities:
Attendant Consoles - 8 per System
Attendant Keys
Loop Keys - 4
Fixed Function Keys - 12
Assignable Function Keys - 18

Trunk Related Capabilities:
Trunk Groups - 32
Trunk Circuits - 104 per System, 100 per Group
Classes of Service - 1 per Trunk Group

Inter PBX Signalling
Inter PBX signalling is provided by the following approved circuit boards:-
TEMHL for E and M circuits (DC5)
TDC10 for DC10 circuits
TAC15 for AC15 circuits

Two and four channel. TGME for long and short lines loop calling without meter pulse detection.

Four channel TIL card for Direct Dial In (DDI) trunks

Siemens Multi-Frequency Signalling (SMFS) is used on AC15 circuits for Inter-MCX working only.

The DIU-D, card provides a 2.048 Mhz digital interface to Megastream type services.

D32 is a Siemens proprietary signalling system approved only for use between MCX's.

Low Speed DPNSS 1 (known as APNSS) is supplied via any approved modem.

The MCCD card provides DPNSS 1 for all systems.

Public Exchange Signalling
Two and four channel. TGME boards are approved for ground start and loop calling. Four variations of each cater for long and short lines with and without meter pulse detection. Dial pulse or MF4 signalling can be provided.

The boards are used for long and short DDI lines.

The MCCD card provides DASS 2.

The DIU-D card provides Channel Associated Signalling on a 2.048 Mhz digital interface.


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Last revised: October 06, 2021