Polycom DOC2579D Manual De Usuario
Chapter A-Glossary
A-6
QCIF
Quarter CIF. A video format with image size of 176x144
pixels that transmits 9.115 Mbps at 30 frames per second
(a quarter of the capacity of CIF). For more information,
see CIF.
pixels that transmits 9.115 Mbps at 30 frames per second
(a quarter of the capacity of CIF). For more information,
see CIF.
QoS
Quality of Service. QoS defines the performance of a
network service, such as the average delay between
packets.
network service, such as the average delay between
packets.
RS-232
A standard for serial interface connection.
SIP
Session Initiation Protocol. An application-layer protocol
designed to work over IP networks. A SIP service defines
the properties and the IP addresses of the SIP network
components.
designed to work over IP networks. A SIP service defines
the properties and the IP addresses of the SIP network
components.
Span
An ISDN line or leased line. A span may be of either T1
(United States) or E1 (Europe) type. Also called a circuit.
(United States) or E1 (Europe) type. Also called a circuit.
SRTP
Encryption of SIP Media is supported using SRTP
(Secured Real-time Transport Protocol) and the AES key
exchange method.
(Secured Real-time Transport Protocol) and the AES key
exchange method.
T1 Line
A 1.5Mb digital switched line used in the United States.
ToS
Type of Service. ToS defines optimization tagging for
routing audio and video packets.
routing audio and video packets.
WAN
Wide Area Network. A communications network that
services a geographical area larger than the LAN.
services a geographical area larger than the LAN.
Whiteboard
An on-screen shared notebook for placement of shared
documents.
documents.
Abbreviation/
Term
Term
Explanation