General Information

Serial #

N/A

Part Number

1

Total Parts

1

AKA

N/A

Patents

N/A

General Description

metal rack/ synthetic and metal boards and circuits

Dimensions

Note: These reflect the general size for storage and are not necessarily representative of the object's true dimensions.

Length

72.0 cm

Width

47.2 cm

Height

115.0 cm

Thickness

N/A

Weight

N/A

Diameter

N/A

Volume

N/A

Lexicon

Group

Communications

Category

Telephony

Sub-Category

N/A

Manufacturer

AKA

Nortel

Country

Canada

State/Province

Unknown

City

Unknown

Context

Country

Canada

State/Province

Unknown

Period

late 1970's to late 1990's

Canada

The DMS-100 switching system was made and designed in Canada and have been in service in telephone central offices across the country and around the world since 1979. The JNET was manufactured between 1978 and 1999 (Ref. 1). When Northern Telecom announced its DMS product line in 1976, it was the first telecommunication equipment manufacturer in the world to offer a complete line of digital telephone switches. As a product it has been extremely successful for Nortel and ongoing sales and service contracts provide a significant, and stable, portion of Nortel's revenue. A Canadian-based company, Northern Telecom/Nortel Networks was one of the most important manufacturers of telecommunications equipment in the world in the 1990s (Ref. 2).

Function

A component of a digital telephone switching system. The junctored network, or JNET, provided the actual pathways through the system that connects subscriber circuits for a call.

Technical

An example of a component of a digital switching system. Digital switches make connections between two telephone lines using a combination of space and time parameters. The time stage consists of a memory device, or time slot interchange (TSI), with a variable and selective delay. This means that a bit arriving in one time slot can be stored and sent in another time slot. The space stage consists of solid state devices (switches, gates or relays) that create a brief physical path to direct the bit stream to the next stage in the switching process. These devices can switch millions of bits of information per second. The JNET has been replaced in most installations by an Enhanced Network (ENET) module that features optical fibre rather than electrical connections. The CMST collection also contains other modules of a DMS switching system including a Central Control Complex [2002.0434]; Test Maintenance Equipment (TME) [2004.0149]; Input/Output Equipment (IOE) [2004.0150]; and two peripheral modules: a Line Concentrating Module (LCM) [2002.0433] and a Link Interface Module (LIM) [2002.0435]. With the acquisition of the Switching Network (the JNET), the museum needs only a Line Trunk Concentrator (LTC) to have all the major components of a DMS switching system (Ref 1). The DMS-100 digital telephone switching system featured an economical codec chip that performed all the analogue-digital-analogue conversions for the interface between the analogue subscriber line and the digital switching system. By combining a large number of discrete devices onto a chip that were previously on a card, the cost and size of lines cards was reduced and reliability increased. This allowed each subscriber line to be assigned it's own card, which made upgrades of individual subscriber's services possible without disrupting service to others. DMS-100's modular design allowed ready upgrading of software and hardware without the need to perform fundamental redesigns. This meant large and small central office switches, toll and overseas switches, even private branch exchanges could all be built using the same kit of hardware and software parts. All this made DMS switches economical, reliable, and relatively easy to service. The DMS-100 digital switching system is essentially an electronic computer operated by stored program control. The Input/Output Equipment (IOE) facilitates human access to this computer. It consists of two Priam 806 hard disk drives, a Cook Electric Co. model 2216 tape drive, an Input/Output Controller and a power supply. The tape drive is used to input program data to the DMS system. The disk drives hold billing records required to generate revenue for the telephone company. The Input/Output Controller consists of cards connecting the system to desktop VT100 or RS232 terminals used by technical personnel. (Ref. 2)

Area Notes

Unknown

Details

Markings

white lettering on fron reads 'DMS 100', 'DSNE 01' and 'nt/ northern/ telecom'/ white labels and lettering on rack back read 'NT8X10AA', 'DSNE 01' and 'DSNE'/ white lettering on rack front read 'eccomc'

Missing

unknown

Finish

rack painted brown/ multicoloured components

Decoration

N/A