DMS switches are divided into four “Functional” areas designed to do certain operations.
These areas are:
- Central Control Complex – Within the Central Control Complex (CCC), the main program in the switch controls the processing of calls, maintenance and administrative routines, and changes the activity for these routines to other areas of the switch.
- Network – The Network Modules (NMs) handle the routing of speech paths between the Peripheral Modules (PMs) and keep these speech connections for the rest of the call.
- Maintenance and Administration – Within the Maintenance and Administration includes Input/Output Controllers (IOCs) – IOCs interface local or remote input/output devices. The I/O devices are used to do testing, maintenance, or administrative functions for the system.
- Peripheral Modules – Peripheral Modules (PMs) are used as interfaces between digital carrier spans (DS-1), analog trunks, and subscriber lines.
DMS 100 is a class 5 local office with the ability to handle 1,000 to 100,000 lines. It can give basic telephone service or expanded to handle IBN custom calling features. The DMS 100 MTX gives cellular radio services. A local office can also be adapted to Equal Access End Office (EAEO).
DMS 200 has the ability to handle from a few hundred to 60,000 trunks. This switch can also serve a Access Tandem (AT) function. The Traffic Operator Position System (TOPS) puts operator services into the DMS 200. Operator Centralization (OC) allows a single operator location by using the TOPS positions to transfer operator services from other DMS-200 toll centers. The Auxiliary Operator Services System (AOSS) let operator services on calls that need outside information (Such as Directory assistance).
A DMS-100/200 is also available and allows local and toll features described above but also includes an Equal Access End Office (EAEO)/Access Tandem (AT) combination. It has the ability to handle up to 100,000 lines or 60,000 trunks.
The Nortel Networks DMS 250 is a high capacity toll system for specialized common carriers needing tandem switching operations.
The Northern Networks DMS 300 is a toll system designed for international use.
The Nortel Networks DMS 500 is a Local and Long Distance system which combines features of the DMS 100 system, DMS 100/200 TOPS and the DMS 250 system in a single, robust platform.