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100 Voice Gateways System Manual
URL Uniform Resource Locator, the global address of documents
and other resources on the World Wide Web. The first part of
the address indicates what protocol to use, and the second
part specifies the IP address or the domain name where the
resource is located.
V.17 An ITU fax standard (1991) that uses TCM (Trellis-Coded
Modulation, a technique for forward error correction)
modulation at 12,000 and 14,400 bps for Group 3 faxes. It
adds TCM to the V.29 standard at 7,200 and 9,600 bps to
allow transmission over noisier lines. It also defines special
functions (echo protection, turn-off sequences, etc.) for
half-duplex operation. Modulation use is a half-duplex version
of V.32bis.
V.29 An ITU standard (1976) for synchronous 4,800, 7,200 and
9,600 bps full-duplex modems using QAM (Quadrature
Amplitude Modulation) on four-wire leased lines. It has been
adapted for Group 3 fax transmission over dial-up lines at
9,600 and 7,200 bps.
V.32bis An ITU standard (1991) for asynchronous and synchronous
4,800, 7,200, 9,600, 12,000 and 14,400 bps full-duplex
modems using TCM and echo cancellation. It supports rate
renegotiation, which allows modems to change speeds as
required.
VLAN Virtual Local Area Network. A group of devices on one or more
LANs that are configured with the same VLAN ID so that they
can communicate as if they were attached to the same wire,
when in fact they are located on a number of different LAN
segments. Used also to create separation between different
user groups.
VoIP Voice over Internet Protocol. Provides an advanced digital
communications network that bypasses the traditional public
switched telephone system and uses the Internet to transmit
voice communication. VoIP enables people to use the Internet
as the transmission medium for telephone calls by sending
voice data in packets using IP rather than by traditional circuit
switched transmissions of the PSTN.