Virtual Conferencing Glossary

U

UDP (User Datagram Protocol) - unreliable networking layer which sits at the same level of networking stack as TCP.

U-Interface - The U-Interface carries ISDN formatted signals over a single pair or wires between a subscriber's location and a telephone company's central office.

Unicast - Application of conferencing, usually over packet-switched networks, where only one user or site receives data. In contrast to this, multicast application, where data is received by more than one user or site.

Unix - Unix is a class of similar operating systems. There are dozens of different implementations or flavours of Unix. For example, Solaris is a flavour of Unix sold by Sun Microsystems. Read the What is Unix? feature article for more information. Technically, Unix is a trademark owned by The Open Group, a non-profit organi-zation. An operating system must comply with a number of standards and pass a battery of tests before it can legally use the name Unix. Otherwise, it referred to as Unix-like or Unix-compatible.

Uplink - The earth station used to transmit signals for a satellite videoconference.

USB USB (Universal Serial Bus) - is a plug and play interface between a computer and peripheral or add on device. USB allows you to add a new device to your computer without having to add an adapter card or even having to shut down your computer.