DMS-100
From Wikipedia, the free encyclopedia
The DMS-100 Switch is the biggest seller of a line of Digital Multiplex System (DMS) telephone exchange switches manufactured by Nortel Networks.
The purpose of the DMS-100 Switch is to provide local service and connections to the PSTN public telephone network. 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 Nework (IBN). It also provides Intelligent Network functions (AIN, CS1-R, ETSI INAP). It is used in countries throughout the world.
Contents |
[edit] Hardware
All power distribution is at -48 VDC (nominal), from which DC to DC converters on every shelf provide other necessary voltages.
Analog lines are terminated on individual line cards, each with its own codec, in pull-out Line Drawers in frames called in the 1980s Line Modules (LM) with 32 lines per drawer, and afterwards called Line Concentrating Modules (LCM) with 64 lines per drawer. Duplicated ringing generators serve each LM or pair of LCM. For DC testing, each line card has a relay to connect it to a test bus. The majority of line cards are 6x17, with three relays for loop start lines. Others include 6x18 which have four or more relays and a slide switch for ground start lines, and 6x21 for P-sets, a special analog telephone with a proprietary Nortel data link 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 simpler replacement for key telephone systems. Each two LCM are served by a Line Group Controller (LGC).
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, usually two T-1 lines per card, ten cards per DTC for a total of 480 ds0 voice channels. At the turn of the century many original 6x50 cards were still in service that cannot perform T-carrier extended superframe signaling. Trunks can also be provisioned on SPM (Spectrum Peripheral Module) capable of handling 2016 DS0s, nearly 4.2x more than the DTC. Internal connections to the time switch are on 2.56 Mbit/s (DS-30) Speech Links, each carrying thirty channels plus synchronization and data channels, on four wires plus a ground wire. Europan PDTC's were complemented by the DTCOI2 and DTCO2.The DTCOI2 designed to run PRI and DPNSS services as per existing PDTCOI and MSB7 peripherals. The DTCO2 was designed to carry CAS and SS7 as per existing PDTCO peripheral.
Time Division switching is performed in E-Net, similar to the Communication Module of 5ESS switch or the Switching Network of EWSD or the Group Switch of AXE telephone exchange.
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.
Hardware and maintenance are administered locally through cathode-ray terminals, through a multilevel menu system called MAPCI. Backups and other hard drive work are administered through a DISKUT command line program.
[edit] See also
[edit] References
[edit] External links
- DMS-100 at the Nortel Networks website
|
|||||||||||||||||||||||
|
|||||
