0-9  A  B  C  D  E  F  G  H  I  J  K  L  M  N  O  P  Q  R  S  T  U  V  W  X  Y  Z ultrahigh frequency (UHF) The range of electromagnetic radio frequencies from 300MHz to 3GHz. undersea See "submarine." universal mobile telecommunications system (UMTS) The European implementation of the 3G wireless phone system. UMTS provides service in the 2GHz band and offers global roaming and personalized features. Designed as an evolutionary system for GSM network operators, UMTS should offer multimedia data rates of up to 2 Mbps. universal product code (UPC) A UPC code is a machine-readable bar code and human readable 12-digit number printed on the side of retail products to help retailers speed up the customer check out process and keep better track of inventory. The UPC code includes a 6 digit manufacturer's identification number and a 5 digit product code. UPC codes were originally created to help grocery stores with their inventory, but have spread to all other retail products. universal serial bus (USB) A hardware interface for low-speed peripherals which can also support MPEG-1 and MPEG-2 digital video. USB’s hot-swap functionality allows devices to be plugged in or unplugged without turning the system off. Devices are plugged into a socket on the PC or into a hub that plugs into the PC. unlevered cash flow (UCF) (free cash flow) The amount of cash a levered company can distribute to its security holders (debt holders, warrant holders, equity holders). upgrade model A model for selling software functionality. This model is most often found with consumer and/or shrink-wrapped software. user network interface (UNI) Specifications for the procedures and protocols between user equipment and either an ATM of frame relay network. The UNI is the physical, electrical, and functional demarcation point between the user and the public network service provider. unshielded twisted-pair (UTP) Wire used for analog telephone circuits.