Multitech MultiModemISDN MTA128ST-USB User Manual page 93

Glossary
V
V.110—One of the terminal rate adaptation protocols for
the ISDN B-channel. V.110 is more hardware-intensive
than the V.120 B-channel standard.
V.120—One of the terminal rate adaptation protocols for
the ISDN B-channel. V.120 is more software-intensive than
the V.110 B-channel standard.
Videotex—A two-way information-retrieval service that can
be accessed by terminals and by a TV set (with installed
decoder). Allows interactive retrieval of information pages
from a central resource. See also ISDN.
virtual circuit—A logical connection. Used in packet
switching wherin a logical connection is established
between two devices at the start of transmission. All
information packets follow the same route and arrive in
sequence (but do not necessarily carry a complete
address).
X
X.25—ITU-T's definition of a three-level packet-switching
protocol to be used between packet-mode DTEs and
network DCEs. X.25 corresponds with layer 3 of the 7-layer
OSI model.
X.75—An ITU-T standard for linking X.25 packet-switched
networks. X.75 defines the connection between public
networks, i.e., for a gateway between X.25 networks.
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