UART Universal Asynchronous Receiver/Transmitter

UAT Union Africaine des Télécommunications / African Telecommunications Union (ATU)

UDP User Datagram Protocol / Protocole de datagramme utilisateur

UID User Identification

UIT Union Internationale des Télécommunications / International Telecommunication Union (ITU)

UMTS Universal Mobile Telecommunications System

UNC Universal Naming Convention

UPT Universal Personal Telecommunications System

UPT Universal Portable Telephone

URC Universal Resource Characteristic

URI Uniform Resource Identifier

URN Uniform Resource Name

USART Universal Synchronous Asynchronous Receiver/Transmitter

USRT Universal Synchronous Receiver/Transmitter