A line card or digital line card is a modular

electronic circuit An electronic circuit is composed of individual electronic components, such as resistors, transistors, capacitors, inductors and diodes, connected by conductive wires or Conductive trace, traces through which electric current can flow. It is a t ...

designed to fit on a separate

printed circuit board A printed circuit board (PCB), also called printed wiring board (PWB), is a Lamination, laminated sandwich structure of electrical conduction, conductive and Insulator (electricity), insulating layers, each with a pattern of traces, planes ...

(PCB) and interface with a

telecommunications Telecommunication, often used in its plural form or abbreviated as telecom, is the transmission of information over a distance using electronic means, typically through cables, radio waves, or other communication technologies. These means of ...

access network An access network is a type of telecommunications telecommunications network, network which connects subscribers to their immediate telecommunications service provider, service provider. It is contrasted with the core network, which connects l ...

. A line card typically interfaces with a twisted pair cable of a

plain old telephone service Plain old telephone service (POTS), or publicly offered telephone service, is basic Voice band, voice-grade telephone service. Historically, POTS has been delivered by Analog signal, analog signal transmission over copper loops, but the term also d ...

(POTS)

local loop In telephony, the local loop (also referred to as the local tail, subscriber line, or in the aggregate as the last mile) is the physical link or circuit that connects from the demarcation point of the customer premises to the edge of the co ...

to the

public switched telephone network The public switched telephone network (PSTN) is the aggregate of the world's telephone networks that are operated by national, regional, or local telephony operators. It provides infrastructure and services for public telephony. The PSTN consists o ...

(PSTN).

Telephone line A telephone line or telephone circuit (or just line or circuit industrywide) is a single-user circuit on a telephone communication system. It is designed to reproduce speech of a quality that is understandable. It is the physical wire or oth ...

cards perform multiple tasks, such as analog-to-digital and digital-to-analog conversion of voice,

off-hook In telephony, on-hook and off-hook are two states of a communication circuit. On subscriber telephones the states are produced by placing the handset onto or off the hookswitch. Placing the circuit into the off-hook state is also called ''seizing ...

detection, ring supervision, line integrity tests, and other

BORSCHT Borscht () is a sour soup, made with meat stock, vegetables and seasonings, common in Eastern Europe and Northern Asia. In English, the word ''borscht'' is most often associated with the soup's variant of Ukrainian origin, made with red b ...

functions. In some

telephone exchange A telephone exchange, telephone switch, or central office is a central component of a telecommunications system in the public switched telephone network (PSTN) or in large enterprises. It facilitates the establishment of communication circuits ...

designs, the line cards generate ringing current and decode DTMF signals. The line card in a subscriber loop carrier is called a subscriber line interface card (SLIC). A line card can terminate a line supporting voice POTS service,

ISDN Integrated Services Digital Network (ISDN) is a set of communication standards for simultaneous digital transmission of voice, video, data, and other network services over the digitalised circuits of the public switched telephone network. ...

service,

DSL Digital subscriber line (DSL; originally digital subscriber loop) is a family of technologies that are used to transmit digital data over telephone lines. In telecommunications marketing, the term DSL is widely understood to mean asymmetric di ...

service, or proprietary ones. Some line cards are capable of terminating more than one type of service. Since an access

network element In computer networks, a network element is 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. According to the Telecommunications Act of 1 ...

is usually intended to interface many users (typically a few thousand), some exchanges have multiple line terminations per card. Likewise, one

can have many line cards.

References

{{DEFAULTSORT:Line Card Telecommunications equipment

See also

References