ADTRAN 1204025L1 Datasheet download pdf (Page 59)

Appendix D Glossary

4-wire Switched 56

An AT&T proprietary 56/64 kbps switched digital data service offered by telco service providers and delivered

to users over 4 copper wires. Compatible with the T1 ESF CSU ACE 4-wire Switched 56 DBU option.

ANSI

American National Standards Institute. Devices and proposes recommendations for international communica-

tions standards.

asynchronous

A method of data transmission which allows characters to be sent at irregular intervals by preceding each char-

acter with a start bit, followed by a stop bit.

bandwidth

The bandwidth determines the rate at which information can be sent through a channel (the greater the band-

width, the more information that can be sent in a given amount of time).

BECN

backward explicit congestion notification. A bit set by a frame relay network to notify an interface device

(DTE) that congestion avoidance procedures should be initiated by the sending device.

bridge

A device that supports LAN-to-LAN communications. Bridges may be equipped to provide frame relay support

to the LAN devices they serve. A frame relay capable bridge encapsulates LAN frames in frame relay frames

and feeds them to a frame relay switch for transmission across the network. A frame relay capable bridge also

receives frame relay frames from the network, strips the frame relay frame off each LAN frame, and passes the

LAN frame on to the end device. Bridges are generally used to connect LAN segments to other LAN segments

or to a WAN. They route traffic on the Level 2 LAN protocol (e.g. the Media Access Control address), which

occupies the lower sub-layer of the LAN OSI data link layer. See also router.

CCITT

Consultive Committee for International Telephony and Telegraphy. A standards organization that devises and

proposes recommendations for international communications. See also ANSI.

carrier detect. A signal generated by a modem or DSU/CSU. CD indicates the presence of a carrier signal on a

communications link.

clocking

An oscillator-generated signal that provides a timing reference for a transmission link. A clock provides signals

used in a transmission system to control the timing of certain functions. The clock has two functions, (1) to gen-

erate periodic signals for synchronization and (2) to provide a time base.

CPE

customer premise equipment. All telecommunications terminal equipment located on the customer premises,

including telephone sets, private branch exchanges (PBXs), data terminals, and customer-owned coin-operated

telephones.

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ADTRAN 1204025L1 Datasheet Page 59