AT&T MERLIN LEGEND Release 3.1 System Planning Manual page 374

Glossary
unrestricted data
channel
UPS
V
VAC
VDC
VMI
voice-band channel
voice mail
voice messaging
interface
W
WATS
wink-start tie trunk
GL–26
System Planning
Unrestricted data channels (also called clear data
channels) allow the transmission of occurrences of more
than seven contiguous zero bits. If an unrestricted data
channel is requested and only restricted channels are
available, the call will be rejected. See also restricted data
channel.
(uninterruptible power supply) Device that connects to the
system to provide 117 VAC to the equipment when the
commercial power source fails.
Alternating-current voltage.
Direct-current voltage.
(voice messaging interface) An enhanced tip/ring port.
A transmission channel, generally in the 300–3400-Hz
frequency band.
Application that allows users to send messages to other
extensions in the system, forward messages received with
comments, and reply to messages.
See VMI .
(Wide Area Telecommunications Service) Service that
allows calls to certain areas for a flat-rate charge based on
expected usage.
Tie trunk on which the originating end transmits an off-
hook signal and waits for the remote end to send back a
signal (a wink) that it is ready for transmission.