Lucent Technologies 5 manual System Overview

MERLIN LEGEND Communications System Release 5.0	Issue 1
System Manager’s Guide 555-650-118	June 1997

2About the System

System Overview Page 2-9

and the parties had hung up, the lamp associated with each connecting cord would go out and the operator knew that the call was complete and the cord could be removed.

The first automatic switch was invented in 1892 by Almon B. Strowger, an undertaker who realized that his competitor was getting all the undertaking business in the town, referred by the town telephone operator—who was also the competing undertaker’s wife! The Strowger switch was an electromechanical device controlled by the caller’s telephone (station switching).

Strowger’s switch was adapted for use in the Bell System in 1919. It was noisy and not very flexible at offering new services but, because it was more cost-effective than human operators, it was directly responsible for making telephone service affordable and universal.

In 1938, the Bell System developed and installed the next innovation in electromechanical switching, and it is still in use in some areas today. It had fewer switches, a sophisticated control mechanism, and lower maintenance. However, like its predecessor, it was not flexible because it couldn’t be programmed.

It was, therefore, a natural progression that led to the idea of using a computer, with its inherent programmable flexibility, to control the switching operation. This new generation of switching technology was called an electronic switching system (ESS). With ever-increasing innovations in technology (beginning with the AT&T No.1 ESS first installed in 1965), the Lucent Technologies 5ESS® digital switching system handles 100,000 lines and 650,000 telephone calls per hour. The newer digital switching systems also interface easily with high-speed digital trunks.

As mentioned earlier, the MERLIN LEGEND Communications System is a switch located on a company’s premises, providing access to powerful features and advanced telephone network applications and services.

System Overview 2

The MERLIN LEGEND Communications System can handle voice and data simultaneously over the same lines, and voice features can enhance the use of data communications. The system accommodates businesses with needs ranging from a few telephones to over 100 telephones. Its modular design allows easy expansion.

Many of the terms and concepts introduced in the beginning of this chapter are used in the system. As illustrated in Figure 2–5, the system allows the connection of incoming trunks from the telephone company’s central office (CO), connected through the system’s control unit to telephones and other system equipment, for example, a PC or fax machine.

There are various types of trunks that provide different functionality. Likewise, a variety of telephones and other equipment can be connected to the system.