Glossary
SLIC | Subscriber Line Interface Circuit. An integrated circuit (IC) providing central |
| interface functionality. |
SOHO | Small office, home office. Networking solutions and access technologies for offices that are not |
| directly connected to large corporate networks. |
T
T.38 | T.38 is an ITU recommendation for allowing transmission of fax over IP networks in real time. |
TCP | Transmission Control Protocol. |
| |
TFTP | Trivial File Transfer Protocol. Simplified version of FTP that allows files to be transferred from one |
| computer to another over a network, usually without the use of client authentication (for example, |
| username and password). |
TN power systems A TN power system is a power distribution system with one point connected directly to earth (ground).
| The exposed conductive parts of the installation are connected to that point by protective earth |
| conductors. |
TOS | Type of service. See CoS. |
U
UAC
UAS
User agent client. A client application that initiates the SIP request.
User agent server (or user agent). A server application that contacts the user when a SIP request is received, and then returns a response on behalf of the user. The response accepts, rejects, or redirects the request.
UDP | User Datagram Protocol. Connectionless transport layer protocol in the TCP/IP protocol stack. UDP |
| is a simple protocol that exchanges datagrams without acknowledgments or guaranteed delivery, |
| requiring that error processing and retransmission be handled by other protocols. UDP is defined in |
| RFC 768. |
user agent | See UAS. |
V
VAD | Voice activity detection. When enabled on a voice port or a dial peer, silence is not transmitted over |
| the network, only audible speech. When VAD is enabled, the sound quality is slightly degraded but |
| the connection monopolizes much less bandwidth. |
| Cisco ATA 187 Analog Telephone Adaptor Administration Guide for SIP (Version 1.0) |
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