Used Nortel DMS telecoms equipment available from Used Telecoms
The DMS-100 Switch is used in many countries all around the world and is the biggest seller of a line of Digital Multiplex System (DMS) telephony switches manufactured by Nortel Networks.
The purpose of the DMS-100 Switch is to provide local service and connections to the PSTN (public switched telephone network) and it is designed to deliver services over subscribers' telephone lines and trunks. It provides Plain Old Telephone Service (POTS), mobility management for cellular phone systems, sophisticated business services such as Automatic Call Distribution (ACD), Integrated Services Digital Network (ISDN), and Meridian Digital Centrex (MDC), formerly called Integrated Business Network (IBN). It also provides Intelligent Network functions (AIN, CS1-R, ETSI INAP). All power distribution is at -48 VDC (nominal), from which DC-DC converters on every shelf provide other necessary voltages.
Analogue lines are terminated on individual line cards, each with their own codec, in pull-out Line Drawers in frames originally called Line Modules (LM) with 32 lines per drawer, and now called Line Concentrating Modules (LCM) with 64 lines per drawer. Duplicated ringing generators serve each LM or pair of LCM. The majority of line cards are 6x17 with three relays for loop start lines. Others include 6x18 which have a slide switch for ground start lines, and 6x21 for P-sets, a special analogue telephone with a proprietary Nortel datalink operating at 8 KHz to provide advanced call handling services. For example, a telephone number may appear on multiple P-sets even though each such telephone has only one pair of wires, thus providing a simplified replacement for key telephone systems.
Transmitters, receivers and other service circuits are in Trunk Module (TM) and Miscellaneous Trunk Module (MTM) shelves. Trunks are on DTC (Digital Trunk Controller) or PDTC (PCM30 Digital Trunk Controller) shelves. Trunks can also be provisioned on SPM (Spectrum Peripheral Module) capable of handling 2,016 DS0s, nearly 4.2 times more than the DTC. Internal connections to the time-switch are on 2.56 MBPS (DS-30) Speech Links, each carrying thirty channels plus synchronization and data channels, on four wires plus a ground (earth) wire. Time Division switching is performed in E-Net.
There are also DMS-200 and DMS-250 variants for tandem switches. The successor to the DMS-100 is the Communication Server 2000, which shares many components and software with the DMS. The significant difference is the addition of VOIP technology into the CS-2000.
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The following is a selection of Nortel DMS equipment currently available from UsedTelecoms.com
