TRUNK UTILIZATION REPORT (TUR)
A computer printout detailing the traffic use of a trunk.

TWO-WIRE CIRCUIT
(1) A channel for transmitting data in one direction at a time.
(2) A short distance channel using a single send/receive pathway, usually 2 copper wires, connecting a telephone to a switch.

TELETYPEWRITER EXCHANGE SERVICE (TWX) (TELEX) (TTY)
A service whereby a customer's leased teletypewriter is connected to a "TWX" switchboard and from there connected over regular toll circuits to a teletypewriter of any U.S. customer who subscribes to a similar service.

UNIFORM CALL DISTRIBUTOR (UCD) (ACD)
A device located at the telephone office or in a PABX which distributes incoming calls evenly among individuals.

UNIFORM SERVICE ORDER CODE (USOC)
The information in coded form for billing purposes by the local telephone company pertaining to information on service orders and service equipment records.

VALUE-ADDED NETWORK SERVICE (VANS)
A data transmission network which routes messages according to available paths, assures that the message will be received as it was sent, provides for user security, high speed transmission and conferencing among terminals.

VIA NET LOSS (VNL)
The lowest loss in dB at which a trunk facility can be operated considering limitations of echo, crosstalk, noise and singing.

VOICE CONNECTING ARRANGEMENT (VCA)
An interface arrangement provided by the telephone company to accomodate the connections of non-carrier provided voice
terminal equipment to the public switched telephone network.