Polycom ViewStation EX4000 - Manual (Page 17)

Chapter 1 - About this Manual
© Polycom, Inc. 7
NFAS Non-Facility Associated Signalling.
NT-1 Network Termination type 1. The device that
converts the ISDN BRI U interface from the
telecommunications service provider to the S/T
interface used by ISDN products and systems.
Pan Move the camera to the left or right.
PBX Private Branch eXchange. A private telephone
switching system connected to common lines
from one or more central offices. Most PBXs allow
analog extensions on the system, allowing access
to special features such as conferencing and
transferring to analog devices. If you are using a
telephone connected to a PBX, typically you will
be required to dial 9 to gain access to an outside
line.
Peripheral
side The portion of a network interface module that
connects to the videoconferencing system. See
also Downstream.
Point-to-point
call A call between two sites.
POTS Plain Old Telephone Service. See PSTN.
PRI Primary Rate Interface.
Private Branch
Exchange See PBX.
PSTN Public Switched Telephone Network. The voice
telephone network accessible to all those with
telephones and access privileges.
PTZ Pan/Tilt/Zoom. Describes the cameras supplied
as part of the ViewStation EX, ViewStation FX,
and VS4000 systems.
QCIF Quarter CIF (Common Intermediate Format). A
video format providing resolution of 176 x 144
pixels. See also CIF, 4CIF, 16CIF.