Polycom DOC2585A - Manual (Page 156)

Chapter A-Glossary
A-2
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-point and 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.
Abbreviation/
Term
Explanation