Appendix A-Glossary

Abbreviation/

Explanation

Term

 

 

 

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.

 

 

QoS

Quality of Service. QoS defines the performance of a

 

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.

 

 

Span

An ISDN line or leased line. A span may be of either T1

 

(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.

 

 

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.

 

 

WAN

Wide Area Network. A communications network that

 

services a geographical area larger than the LAN.

 

 

Whiteboard

An on-screen shared notebook for placement of shared

 

documents.

 

 

A-6

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Image 188
Polycom DOC2560C manual Qcif