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To use the glossary, simply click on the first letter of
the term of interest below:
S
- SDSL
- Symmetrical Digital Subscriber Line, symmetrical, like HDSL but operating over a single pair, SDSL provides full duplex symmetrical connectivity at 2.3 Mbps over distances up to 6.7 Km (4.2 miles). This type of transmission does not support telephony over the same physical
pair as do ADSL and RADSL.
- SECAM
- Systeme Electronique Couleur Avec Memoire, the 625-line color television standard used in France and the former Soviet Union.
- Send-Only Codec
- A video codec only able to originate (transmit) communications signals, for use at the sending location in point-to-multipoint or broadcast applications, and for security and military applications when two-way codec communication between locations is not possible or required.
- SIP
- Session Initiation Protocol. An emerging Internet standard to facilitate mixed-media sessions over IP. Sessions may span the range of services from voice-only to full multimedia conferencing; multipoint is also included.
- SGML
- Standard Generalized Markup Language, the superset from which HTML was derived.
- SMDS
- Switched Multi-megabit Data Service, a cell-relay wireless technology for providing data between 1.5-Mbps and 45-Mbps.
- SLIP
- Serial Line Interface Protocol, an Internet access method. Compare with PPP.
- SMPTE
- Society of Motion Picture and Television Engineers
- SNA
- System Network Architecture (IBM usage).
- SNMP
- Simple Network Management Protocol (TCP/IP)
- SNR
- Signal-to-Noise Ratio.
- Softswitch
- A concept that was perhaps first formalized by the ITU-T Working Party developing the nascent T.130 series recommendations in the mid-1990s. Several key concepts included distributed network intelligence, distributed switching (time and space), and the separation of the multimedia
content and the switching logic layers.
Now, there is an industry consortium promulgating standards-based aspects including:
- H.323 Videoconferencing and Multimedia
- SIP Session Initiation Protocol
- RTP Real-time Transport Protocol
- RTSP Real-Time Streaming Protocol
- MGCP Media Gateway Control Protocol
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Depending upon the point of view of the particular industry sector, Softswitch technology may result in the replacement of the end-office switch for the CLEC for the provision of telephony and facsimile. At the other extreme, Softswitch can be a flexible, intelligent packet switching arrangement
in a mixed multimedia environment. Internet services like VoIP will also likely be part of this technology mix, once the quality of service issues are fully resolved.
- SONET
- Synchronous Optical NETwork
- Spatial Filtering
- In video compression, removal of redundant information on a line-by-line basis by discarding diagonally adjacent pixels. Also known as field subsampling, loop filtering, H.261, H.263 usage.
- SPL
- Sound Pressure Level, in acoustic measurement.
- SQCIF
- Sub-Quarter Common Intermediate Format. Describes a subset of the type of coded video signals transmitted when using ITU-T Rec. H.261 and H.263 coding methods. See CIF.
- SSFH
- Spread Spectrum Frequency Hopping, used for data radio transmission from the low 10's of MHz to the multi-GHz bands, especially under high interference conditions. Popular for wireless LANs, for example
- STDM
- Statistical Time-Division Multiplexer, (statmux or statistical multiplexer), a device which combines a number of time-varying bit streams into a single bit stream for transmission. In DBS, may dynamically allocate bandwidth through control signals to MPEG2 video codecs.
- STDM
- Statistical Time Division Multiplex, used by DBS and for mixed data requirements to improve network utilization.
- SVC
- Switched Virtual Circuit (frame relay use).
- Synchronous
- With reference to video and data signals and devices: being
precisely in step, or happening together in time.
- Syndrome
- A code transmitted along with data to enable correction of transmission-induced errors in the received data. See Forward Error Correction. Compare with Checksum.
To use the glossary, click on the first letter of
the term of interest:
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© 2006 - 2011 Acleris
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