Practical TCP/IP and Ethernet Networking- P62: The transmitter encodes the information into a suitable form to be transmitted over the communications channel. The communications channel moves this signal as electromagnetic energy from the source to one or more destination receivers. The channel may convert this energy from one form to another, such as electrical to optical signals, whilst maintaining the integrity of the information so the recipient can understand the message sent by the transmitter | AppendixA Glossary 287 SDLC Synchronous Data Link Control. IBM standard protocol superseding the bisynchronous standard. Serial transmission The most common transmission mode in which information bits are sent sequentially on a single data channel. Session layer Layer 5 of the ISO OSI reference model concerned with the establishment of a logical connection between two application entities and with controlling the dialog message exchange between them. Simplex transmissions Data transmission in one direction only. Slew rate This is defined as the rate at which the voltage changes from one value to another. SNA Systems Network Architecture. Standing wave ratio The ratio of the maximum to minimum voltage or current on a transmission line at least a quarter-wavelength long. VSWR refers to voltage standing wave ratio. Star A type of network topology in which there is a central node that performs all switching and hence routing functions. STP Shielded Twisted Pair. Switched line A communication link for which the physical path may vary with each usage such as the public telephone network. Synchronization The co-ordination of the activities of several circuit elements. Synchronous transmission Transmission in which data bits are sent at a fixed rate with the transmitter and receiver synchronized. Synchronized transmission eliminates the need for start and stop bits. T TCP Transmission Control Protocol. TDR Time Domain Reflectometer. This testing device enables the reflections user to determine cable quality with providing information and distance to cable defects. Telegram In general a data block which is transmitted on the network. Usually comprises address information and check characters. 288 Practical TCP IP and Ethernet networking Temperature rating The maximum and minimum temperature at which an insulating material may be used in continuous operation without loss of its basic properties. TIA Telecommunications Industry Association. Time sharing A method of computer .
