c routing Routing in which the routes are manually entered into the routing table. station A computer or device that can send and receive data over a communication line. statistical multiplexer A multiplexer that uses the idle time of connected devices to carry data traffic from active devices. STDM (Statistical Time Division Multiplexing) A method of TDM in which time slots on a shared medium are allocated on demand. STM (Synchronous Transport Module) The basic building block of SDH. STM-1 con- sists of 9 rows of 270 bytes each. The first 9 columns contain the section and line overhead for all STS-3s. The remaining 261 columns contain the combined envelope capacity of the component STS-1s. Common STM levels include STM-0, STM-1, STM-4, STM-16, STM-64, and STM-256. stop bit In asynchronous transmission, the quiescent state following the transmission of a character; usually required to be at least 1-, 1.5-, or 2-bit times long. stop element The last bit of a character in asynchronous serial transmission, used to ensure recognition of the next start element. store-and-forward A technique that involves accepting a message or packet on a communi- cations pathway, retaining it in memory, and retransmitting it to the next station. Synonymous with message switching. STP (shielded twisted-pair) Two insulated wires in a cable that is wrapped with metallic braid or foil to prevent interference and to provide noise-free transmission. STP (signal transfer point) A switch that is responsible for translating SS7 messages and then routing those messages between the appropriate network nodes and databases. STP (Spanning Tree Protocol) STP (Spanning Tree Protocol) A protocol for complex bridge configurations defined by IEEE 802. 1D. This protocol ensures that a complex bridge configuration has no loops (i.e., there is one and only one possible path from any particular endpoint to any other). streaming media Data that is transferred so that it can be processed as a steady and contin- uous stream. Streaming technologies are increas