to blogs. RTMP (Real-Time Messaging Protocol) A realtime streaming protocol developed by Adobe for using Flash servers to improve streamed audio, video, and data over the Internet. It is now used with other Adobe programs. According to Adobe, most of the RTMP specifications are open to developers to create applications compatible with Adobe Flash Player. RTP (Real-Time Transport Protocol) An IETF standardized protocol for transmitting multimedia in IP networks. RTP is used for the "bearer" channels, the actual voice, video, and image content. SDH (Synchronous Digital Hierarchy) www.TechnicalPDF.com A world standard of synchronous optical speeds. The basic SDH speed starts at 155 Mbps, also called STM-1 (Synchronous Transport Mode-1) in Europe. SONET is a subset of SDH. server A specialized, shared computer on the LAN or in a carrier's network containing files such as e-mail or applications. It can be used to handle sharing of printers, e-mail, and other applications. set-top box A device connected to a television that allows access to various content, including pay-per-view programming. Set-top boxes can be used to distribute content to other TVs and devices. Newer models contain hard drives and multiple tuners. They can be used to watch one program while recording a different show, and to pause and rewind programs. signaling gateway A type of media gateway that converts signaling from IP networks to that compatible with traditional, circuit- switched networks, and vice versa. SIM (Subscriber Identification Module) A clip-on or internal card with microchips in mobile handsets that stores user identity and other information such as speed-dial lists and e-mail addresses. CDMA phones do not have SIM cards. SIP (Session Initiation Protocol) A signaling protocol used to establish sessions over IP networks, such as those for telephone calls, audio conferencing, click-to-dial from the Web, and instant message exchanges between devices. It is also used to link IP telephones from different manufacturers to SIP- compatible