GLOSSARY 449
translation The process of interpreting or modifying dialed digits for incoming or
outgoing calls and allows the call to progress through the network.
trunk A communications channel between two points. It often refers to
large-bandwidth telephone channels between major switching centers,
capable of transmitting many simultaneous voice and data signals.
twisted pair Two insulated wires twisted together with the twists varied in length to
reduce potential signal interference between the pairs. Twisted pair is the
most common medium for connecting telephones, computers and
terminals.
UPS Uninterruptible Power Supply. A secondary power source attached to a
piece of hardware, for example a server, which provides backup power
for conducting an orderly shutdown if the server’s normal power supply
fails.
UTP Unshielded Twisted Pair. Two insulated wires twisted together with the
twists varied in length to reduce potential signal interference between the
pairs. The standard cabling used for telephone lines and Ethernet
10BASE-T.
virtual LAN A logical, rather than a physical, LAN that includes workgroups drawn
together for business reasons or for a particular project regardless of the
location of the members.
VPIM Voice Profile for Internet Mail. A set of Internet protocols that merges
voice messaging and e-mail. VPIM lets voice mail and e-mail servers
exchange messages across TCP/IP-based intranets and the Internet.
VTL Virtual Tie LIne. Allows several NBX domains to create tie lines on
demand and to place calls over a WAN. Uses peer-to-peer connections for
the audio.
WAN Wide Area Network. A network that covers a larger geographical area
than a LAN. In a WAN, telecommunications links are normally leased from
the appropriate Public Telephone Operator (PTO).
wiring closet The location, usually a physical box, in which the cabling on one floor of a
building is terminated.
workstation Another name for a computer, typically running UNIX or the Windows NT
operating system.