Polycom VIEWSTATION Training Manual page 40

End-User Training Guide: ViewStation
MPEG
– Motion Pictures Experts Group: This is a standard for motion video.
Multiway
– Communication between more than two sites. Multiway
communication may occur through a digital switch or through an analog
gateway.
Multipoint Control Unit
connected in a videoconference. Sometimes called a digital switch or video
bridge.
NTSC
– North American standard for analog video format. National
Television Systems Committee.
Out of band
– Transmission taking place external to allocated bandwidth. A
video call with out-of-band audio requires a separate phone line for the audio.
PAL
– European standard for analog video format.
PCCITT
– International Telephone and Telegraph Consultative Committee.
Now known as ITU-T. An international body that sets worldwide
telecommunications standards, such as the Px64 standard for
videoconferencing.
Pixel
– Picture element; a measure of resolution for video format.
Primary Rate Interface (PRI)
64 kbps B channels and one 64 kbps D channel used for signaling.
POP
– Point-of-Presence. The location or office where a line from an Inter-
Exchange Carrier (IXC) connects to the local telephone company or directly
to the user.
POTS
– Plain Old Telephone System. The analog phone system (including
telephones, modems, central offices switches, etc., currently in use around
the world.
Px64
– The ITU-T's international video standard which provides a standard
algorithm for video compression and decompression. Formally known as
H.261, it was adopted in December 1990.
– Device which allows more than two sites to be
– An ISDN subscriber line consisting of 23
VSGi - Polycom ViewStation End-user Training Guide
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