Polycom DOC2560A manual Abbreviation, Explanation, Term, Chapter A-Glossary

Chapter A-Glossary

Abbreviation/	Explanation
Term
BRI	Basic Rate Interface. A type of ISDN connection for
	transiting data, consisting of 3 channels: two B-channels
	(each of 64 Kbps) and one D-channel (16 Kbps).
Carrier	A telephone or other company that provides
	telecommunication transmission services.
CIF, 4CIF, QCIF	Common Intermediate Format, an optional part of the
	ITU-T's H.261 and H.263 standards. CIF specifies 288
	non-interlaced luminance lines, that contain 176 pixels.
	CIF can be sent at frame rates of 7.5, 10, 15, or 30 per
	second. When operating with CIF, the amount of data to
	transmit cannot exceed 256 K bits (where K equals
	1024).The CIF video format has the capacity to transmit
	video images of 352x288 pixels at 36.45 Mbps and 30
	frames per second. A 4CIF format has four times the
	capacity of CIF; QCIF has quarter the capacity of CIF.
Codec	Coder-decoder. A device that converts voice and video
	into digital code, and vice versa. Refers to the endpoint
	video camera and video board that are used for
	videoconferencing.
Conference	Connection between two or more endpoints exchanging
	video and audio information. If only two endpoints are
	involved, a conference is called point-to-pointand no
	MCU is required. If more than two endpoints are involved,
	it is called a multipoint conference, and an MCU
	(Multipoint Control Unit) is required as the management
	system. For more information, see MCU.
CSU	Channel Service Unit. Customer-provided equipment that
	is used as an interface between a communication network
	and the data terminal.
DBA	Dynamic Bandwidth Allocation. Used to allocate the
	bandwidth needed to transmit the additional packets. for
	LPR.

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