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Appendix : Glossary 139
TDMA Time Division Multiplexing Adapter—A device that allows analog voice and data
devices to work through an ISDN connection. The terminal adapter is a protocol
converter that adapts equipment not designed for ISDN, such as phones, faxes,
and modems.
TFTP Trivial File Transfer Protocol—simplified version of the File Transfer Protocol (FTP)
that transfers files but does not provide password protection or user directory
capability.
Total Control Manager TCM—See IP Telephony Manager.
UCF Unregistration Confirm
UDP User Datagram Protocol—Connectionless transport layer protocol in the TCP/IP
protocol stack. UDP is a simple protocol that exchanges datagrams without
acknowledgments or guaranteed delivery, requiring that error processing and
retransmission be handled by other protocols. UDP is defined in RFC 768.
UI User Interface—In telephony terms, this is the reference point for the BRI
connection between a telephone company local loop and the customer
equipment.
UL Underwriters Laboratory—A non-profit laboratory that examines and tests items
submitted by their manufactures for safety.
UNC Names Universal Naming Convention Names—Naming conventions for file names or
other resources beginning with ‘\\’, indicating that they exist on a remote
computer.
URJ Unregistration Reject—This is a call flow message.
URQ Unregistration Request—This is a call flow message.
UTP Unshielded Twisted Pair— Four-pair wire medium used in a variety of networks. It
consists of copper conductors that are electrically balanced.
VDE Verbund Deutscher Electronicker—Federation of German Electrical Engineers,
similar to the IEEE in the United States.
VFPD Virtual Front Panel Display—Refers to the GUI display of the Total Control 1000
chassis.
VoIP Voice Over Internet Protocol—A set of protocols for managing the delivery of
voice and data information using the Internet Protocol (IP). Voice and data
information is sent in digital form in discrete packets over the Internet instead of in
analog form over the public switched telephone network (PSTN). A major
advantage of VoIP is that it avoids the tolls charged by ordinary telephone service.
VRAM VIrtual Random Access Memory
WAN Wide Area Network—Public or private computer network serving a wide
geographic area.