5ESS Switch

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The 5ESS Switch is the Class 5 telephone switching system sold by Lucent Technologies. It is also manufactured overseas under license. This digital central office telephone circuit switching system is used by many telecommunications service providers.

1 History
2 Archictecture
3 Administration
4 See Also
5 References

[edit] History

5ESS service first appeared in Seneca, Illinois (815 Area Code) in 1982. It has approximately half the US installed base of telephone exchanges. It is also exported, and manufactured overseas under license. Lucent was formerly a division of AT&T and historically known as Western Electric or WECO.

[edit] Archictecture

The 5ESS is primarily UNIX-based and runs on a Time-Space-Time (TST) topology. The Time-Slot-Interchangers (TSI) in the Switching Modules (SM), one per several hundred to few thousand trunks or lines, sport their own processors, which perform most call handling processes, thus lessening the load on the Central Administrative Module or main computer. Originally the peripheral processors were to be Intel 80286, but those proved inadequate and the system was introduced with Motorola 68000 series processors.

T-carrier spans are terminated, one or two per card, in Digital Line Trunk Units which concentrate their DS0 channels into the TSI. Larger DS3 signals can also have their DS0 signals switched, without demultiplexing them into DS1. SMs are connected by optical fibers to the Communications Modules for switching to other SMs.

In contrast to Nortel's DMS-100 which uses individual line cards with a codec, most lines are on two stage analog space division concentrators or Line Units, which connect a few hundred lines as needed to the 8 Channel cards that each contain 8 codecs, and to high level service circuits for ringing. Both stages of concentration are included on the same grid boards.

Some lines, especially ISDN, are served by individual line cards.

[edit] Administration

The system is administered through an assortment of teletypewriter "Channels", such as the TEST channel and Maintenance channel. Typically provisioning is done using a one of two methods - a command line interface (CLI) called RCV:APPTEXT, and through a menu-driven RCV:MENU. RCV stands for Recent Change/Verification. Most service orders, however, are admininstered through Recent Change Memory Administration Center (RCMAC).

Some of this information taken from http://www.alleged.com/telephone/5ESS/