7E Communications
   

Glossary Terms Beginning U

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N : O : P : Q : R : S : T : U : V : W : X : Y : Z

U
Rack-height unit: a unit of measurement of height for equipment racks, where 1 U = 1.75 in (44.5 mm); also referred to as RU.
U-interface
The point at which the ISDN telephone line terminates at a subscriber's premises.
UMTS
Universal Mobile Telecommunication System: ETSI system.
Unilateral
Transmission from one origin to one destination only.
Upconverter
Earth station equipment to convert from IF to RF frequency: transforms the modulated IF signal from the modulator up to the desired transmit frequency by a process of frequency shifting or conversion.
Uplink
Earth station used to transmit signals to a satellite; the transmit earth station-to-satellite connection.
UTC
Universal time co-ordinated: measurement of time, locked to an atomic clock reference, particularly used in space science and engineering; virtually the same as Greenwich Mean Time.