Line card
Encyclopedia
A line card or Digital Line Card is a modular electronic circuit on a printed circuit board
, the electronic circuits on the card interfacing the telecommunication lines coming from the subscribers (such as copper wire or optical fibers) to the rest of the telecommunications access network
.
A line card commonly interfaces the twisted pair
cable of a POTS
local loop
to the public switched telephone network
(PSTN). Telephone line
cards used in PSTN perform multiple tasks such as analog-to-digital
and digital-to-analog
conversion of voice, off-hook
detection, ring supervision, line integrity tests, and other BORSCHT
functions. In some telephone exchange
designs the line cards generate ringing
current and decode DTMF signals. The line card in a Subscriber Loop Carrier is commonly called a Subscriber Line Interface Card (SLIC).
A line card can terminate a line supporting voice POTS
service, ISDN service, DSL service, or proprietary ones. Some line cards are capable of terminating more than one type of service.
Since an access network element is usually intended to interface many users (typically a few thousands) some exchanges have multiple line terminations per card. Similarly, it is common to have many line cards in the same network element
.
Line Card less often refers to a brochure
listing manufacturers and products sold by a third party, for example a distributor or representative..
Printed circuit board
A printed circuit board, or PCB, is used to mechanically support and electrically connect electronic components using conductive pathways, tracks or signal traces etched from copper sheets laminated onto a non-conductive substrate. It is also referred to as printed wiring board or etched wiring...
, the electronic circuits on the card interfacing the telecommunication lines coming from the subscribers (such as copper wire or optical fibers) to the rest of the telecommunications access network
Access network
An access network is that part of a telecommunications network which connects subscribers to their immediate service provider. It is contrasted with the core network, which connects local providers to each other...
.
A line card commonly interfaces the twisted pair
Twisted pair
Twisted pair cabling is a type of wiring in which two conductors are twisted together for the purposes of canceling out electromagnetic interference from external sources; for instance, electromagnetic radiation from unshielded twisted pair cables, and crosstalk between neighboring pairs...
cable of a POTS
Plain old telephone service
Plain old telephone service is the voice-grade telephone service that remains the basic form of residential and small business service connection to the telephone network in many parts of the world....
local loop
Local loop
In telephony, the local loop is the physical link or circuit that connects from the demarcation point of the customer premises to the edge of the carrier or telecommunications service provider's network...
to the public switched telephone network
Public switched telephone network
The public switched telephone network is the network of the world's public circuit-switched telephone networks. It consists of telephone lines, fiber optic cables, microwave transmission links, cellular networks, communications satellites, and undersea telephone cables, all inter-connected by...
(PSTN). Telephone line
Telephone line
A telephone line or telephone circuit is a single-user circuit on a telephone communication system...
cards used in PSTN perform multiple tasks such as analog-to-digital
Analog-to-digital converter
An analog-to-digital converter is a device that converts a continuous quantity to a discrete time digital representation. An ADC may also provide an isolated measurement...
and digital-to-analog
Digital-to-analog converter
In electronics, a digital-to-analog converter is a device that converts a digital code to an analog signal . An analog-to-digital converter performs the reverse operation...
conversion of voice, off-hook
Off-hook
In telephony, the term off-hook has the following meanings:# The condition that exists when a telephone or other user instrument is in use, i.e., during dialing or communicating. Note: off-hook originally referred to the condition that prevailed when telephones had a separate earpiece , which hung...
detection, ring supervision, line integrity tests, and other BORSCHT
BORSCHT
BORSCHT is an acronym for:Battery supply to subscriber lineOvervoltage protectionRinging current supplySupervision of subscriber terminalCoder and decoderHybrid, 2 wire to 4 wire conversionTesting...
functions. In some telephone exchange
Telephone exchange
In the field of telecommunications, a telephone exchange or telephone switch is a system of electronic components that connects telephone calls...
designs the line cards generate ringing
Ringing (telephony)
A ringing signal operates a bell or other ringtone generator in a telephone, to alert the user to an incoming telephone call.Telephone bells or ringtones are rung by impressing a 105-volt RMS 20-Hertz sine wave across the tip and ring conductors of the subscriber line. This signal is produced by a...
current and decode DTMF signals. The line card in a Subscriber Loop Carrier is commonly called a Subscriber Line Interface Card (SLIC).
A line card can terminate a line supporting voice POTS
Plain old telephone service
Plain old telephone service is the voice-grade telephone service that remains the basic form of residential and small business service connection to the telephone network in many parts of the world....
service, ISDN service, DSL service, or proprietary ones. Some line cards are capable of terminating more than one type of service.
Since an access network element is usually intended to interface many users (typically a few thousands) some exchanges have multiple line terminations per card. Similarly, it is common to have many line cards in the same network element
Network element
A network element is usually defined as a manageable logical entity uniting one or more physical devices. This allows distributed devices to be managed in a unified way using one management system....
.
Line Card less often refers to a brochure
Brochure
A brochure is a type of leaflet. Brochures are most commonly found at places that tourists frequently visit, such as museums, major shops, and tourist information. Brochure racks or stands may suggest visits to amusement parks and other points of interest...
listing manufacturers and products sold by a third party, for example a distributor or representative..
See also
- 5ESS switch5ESS SwitchThe 5ESS Switch is a Class 5 telephone electronic switching system sold by Alcatel-Lucent. This digital central office telephone circuit switching system is used by many telecommunications service providers.-History:...
- DMS-100DMS-100The DMS-100 Switch is a line of Digital Multiplex System 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...
- Plain Old Telephone ServicePlain old telephone servicePlain old telephone service is the voice-grade telephone service that remains the basic form of residential and small business service connection to the telephone network in many parts of the world....
(POTS)