TRG
Trunk Group
TRS/Barring
Toll Restriction/Call Barring
U
UCD
Uniform Call Distribution
UM
Unified Messaging
UPS
Uninterruptible Power Supply
V
VM
Voice Mail
VoIP
Voice over Internet Protocol
VPN
Virtual Private Network
VPS
Voice Processing System
X
XDP
EXtra Device Port
List of Abbreviations
Feature Guide
7