Glossaries

• Supervisory Auditory Tone (SAT)
• A high pitched, inaudible tone used between mobile phones and the tower to setup calls or navigate the geolocation of cell phones.
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• Supervisory Control and Data Acquisition (SCADA)
• A generic name for a computerized system that is capable of gathering and processing data and applying operational controls over long distances. Typical uses include power transmission and distribution and pipeline systems.
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• Station Class Mark (SCM)
• A 4 or 8 bit number transmitted by a mobile phone to the tower which contains information about the type of transmission you are sending.
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• Serial Communications Port (SCP)
• A form of communication where bits are transferred one at a time over a channel. As compared to parallel transmission, where bits are sent at the same time. The term also typically refers to RS-232 type hardware connectors as opposed to newer USB, Firewire, or Ethernet interfaces.
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• Synchronous Digital Hierarchy (SDH)
• The Synchronous Digital Hierarchy (ETSI) makes the transport over fiber STM1/4/16/64/256 links of the TDM circuits, ATM circuits and Ethernet EoS within a hierarchy of transport using VCxx containers. Main advantages of SDH are to carry independent circuits, with each independent synchronization, the absolute QoS because the bandwidth is permanently reserved in the pipe, the mechanism of protection in ring, bus or Mesh fiber infrastructures, and the end-to-end management of transmission quality.
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• Sealing Current
• A low level current, typically 1 to 20 milliamps, that burns off any oxidation film that may have built up on the switch contacts. This prevents line noise or transmission irregularities that may be caused by the oxidation.
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• Severely Errored Second (SES)
• Similar to an Errored Second, except that it contains much more path code violations or alarm indication signals.
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• Severely Errored Second Ratio (SESR)
• The ratio of severely errored seconds (SES) to the total number of seconds during any given measurement interval.
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• Server GPRS Support Node (SGSN)
• Works with the Gateway GRPS Support Node. The SGSN delivers packets to cell phones within its given geographical access area.
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• Subscriber Identity Module (SIM)
• The component inside a mobile phone or mobile device that contains all the subscriber information. It is commonly called a SIM card because it is a small, transferable card.
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• Simplex
• Communication in only direction only. Examples include a pager and mouse-to-CPU connection.
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• Simple Network Management Protocol (SNMP)
• A protocol used in TCP/IP systems to manage devices inside the network. It is often used to collect performance statistics and monitor for alarm conditions. It can also be used to control the device and set configurations.
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• Signal to Noise Ratio (SNR)
• Ratio of signal power to noise power, it is a measure of transmission quality. Often expressed in decibels (dB).
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• Synchronous Optical Network (SONET)
• The Synchronous Optical Networking (ANSI) is the same technology and supports the same advantage as SDH but with ANSI definitions and transport over fiber with OC3/12/48/192/768 hierarchy.
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• Strict Priority (SP)
• Method of forwarding packets from a router. Packets with a higher priority are always sent out first, regardless of how many there are. If there are a lot of high priority packets, it is possible that lower priority packets will be excessively delayed or dropped. Compare to Weighted Round Robin.
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• Signaling Tone (ST)
• In telephone communications, a periodic tone that is sent in-band (along with the data) to indicate a condition. Common signaling tones include a dial tone, ringing tone, and a busy tone.
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• Synchronous Transport Module, level 1 (STM-1)
• A type of SDH format that specifies a frame structure for a SDH cell. It has a bit rate of 155.52 Mbps.
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