Mike's PBX Cookbook

MITEL Information

THE SX-200

The SX-200 system has been the company's flagship since its introduction in 1978. The SX-200 system was developed in 1977. It was designed for the under-100 market, and was the first system to bring the sophistication of distributed processing to that market segment. Almost 50,000 of these systems are still in use around the world. The SX-200 was introduced with a feature package called Generic 202. Software and feature enhancements have continued from 1978, and now include generics supporting ACD, auto attendant, and interactive voice mail. Hardware enhancements have included an LCD attendant console, the SUPERSET 3 and 4, and the digital SUPERSET 3DN, 4DN, and the 400 series of telephones.

Every enhancement made to the SX-200 line has remained completely compatible with the first SX-200 shipped in 1978.

In 1985, Mitel introduced a hybrid SX-200 Digital PBX. A complete migration path was supported for users of the earlier analog switches, so that no users would be trapped in the old technology and forced to purchase a completely new switch. A fully digital version of the SX-200 followed in 1986. This system incorporated Mitel's DX chip, used in the digital switching matrix, and Mitel filter codes used to convert analog signals to digital PCM format.


A 672-port system was introduced in 1988 as an expansion for existing 250-line systems and for new customers needing up to 500 lines.

Generic 1003 software, introduced at the same time, offered advanced business features such as modem pooling and DATASETs capable of synchronous/asynchronous transmission. In addition, Mitel introduced a flexible ACD telemarketing package.

In 1990, Generic 1004 followed, providing an office feature package that supported key system functionality for companies that wanted a departmental key system within their PBX environment. A Front Desk terminal provides a low-cost alternative to a PMS for smaller hotel/motel operators. Enhanced Subattendant features were also included.


1987 saw the SX-50 System introduced. The SX-50 is a digital switching product for the 16-100 line market, particularly aimed at small businesses with especially sophisticated needs not normally met by key systems designed for that line size. The SX-50 is popular in the hospitality and healthcare markets. Packing big-system features into a wall- mounted cabinet, the SX-50 provides a complete range of general business features. For further application specialization, packages for conferencing, call forwarding, integrated voice mail auto attendant and networking were made available to further user customization.

THE SX-2000

1984 brought the SX-2000 Integrated Communications Systems (ICS). This larger-sized PBX starts at 400 lines and can be grown to several thousand. This system added support for integrated data capabilities and provided an interface between host computer, PCs, terminals and other office data equipment.

A smaller version of the SX-2000, the SX-2000S (for "small"), was brought out in 1987. The SX-2000VS ("very small"), followed the SX-2000S in 1989. These switches were aimed at rounding out Mitel's line, enabling purchase of exactly as much switching capacity as was needed by the customer.


HCI is a high-level protocol operating at the OSI Applications layer, enabling it to function independently of the transport medium. HCI's purpose is to enable bi-directional communications between the PBX and a host computer. The computer can monitor the status of events on the PBX, and also initiate PBX events.


Mitel's proprietary line of telephone handsets is the SUPERSET family. Additional models in the SUPERSET family of handsets, the 401, 410, 420, and 430 were introduced in 1991.

The high end of the SUPERSET line, the 430, is unique in featuring a bitmapped LCD display, which can then be updated by reprogramming the software on the switch to change the graphics, instead of having to pull a ROM or replace the whole handset. Custom graphics can also be developed for the set.


The SX-200 LIGHT and SX-2000 LIGHT are the company's latest switching offerings. Contrary to the image the name conjures for most people, the LIGHT name does not mean "reduced," but that the switch incorporates fiber optic technology. Fiber optic cabling connects the control cabinet to each of the peripheral cabinets.

The SX-200 LIGHT also represents a new approach to design of the switch. Instead of the "big black box in the basement," the SX-200 LIGHT is made up of a control cabinet and up to 7 96-port peripheral cabinets. The SX-2000 LIGHT can accept up to 11 peripheral cabinets.

Peripheral cabinets can be distributed departmentally or by application. The SX-2000 main control cabinet is about the size of a tower PC. This not only eliminates the need for a dedicated equipment room, but means that with the distributed nodes, only lightweight fiber optic cable will have to be pulled in existing conduit between departments and floors to connect the units, rather than having to rewire multi-pair cable between departments and floors.

3000' feet of fiber optic cable can be carried on one arm. Fiber links between peripheral nodes can be up to 3300 feet long.

Software for this switch is LIGHTWARE 15, and is available now. LIGHTWARE's operating system is UNIX-based, compatible with both North American and European standards. LIGHTWARE also includes ISDN interface capability, DTMF Automatic Number Identification (ANI) and DTMF Dialed Number Identification Service (DNIS).

More modules and additional hardware can be coupled to the system to increase capabilities. Voice mail, ACD, specialized auto attendant and more can all be integrated directly to the LIGHT.

If a user chooses to upgrade their existing Mitel switch to a LIGHT system, they may have to replace some cabinets and control hardware, but LIGHT can still make use of control cards and analog/digital interfaces from older equipment. This is right in line with Mitel's principle of never forcing the user to scrap all their existing hardware and start over.


The PC brought power to the desktop. Now individuals, or workgroups on LANs could focus on solving their own unique challenges, with their own software and their own databases.

To continue the analogy, we are now seeing a dramatic reaction by these "empowered" computer users to the feudalism/tribalism of proprietary hardware and operating systems. The result is an emerging "glasnost" of open systems that is rapidly becoming platform-independent.

The reason behind these changes are not isolated. They reflect fundamental shifts in the way corporations are structured, the way workgroups are given freedom and responsibility, and the use of sophisticated technology by small business.

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