UDP
User Datagram Protocol. The real-time equivalent of TCP, used for voice and video data where there is no time for error correction.
UI
User Interface. See GUI.
UM
Unified Messaging. A system whereby all email, voice and fax messages are centralised.
UMTS
Universal Mobile Telecommunications System. The successor to GSM also referred to as ‘third generation’ or 3G. See also W-CDMA.
UPS
Uninterruptible Power Supply. Works like a battery. Prevents you losing your work in the event of a power failure, and allows you to keep on working until the power is restored. Mostly used by businesses
USB
Universal Serial Bus. Interconnect standard allowing a number of peripherals to be connected via a single port. Maximum data rate of 12 Mbits/s
