A B C D E F G H I J K L M N O P Q R S T U V W X Y Z
Satellite - Electronic device or platform, self sustained, which orbit the earth with an orbit of approximately 22,000 miles. Communications satellites transmit / receive signals in the microwave range; some uses are broadcast TV, telecommunications, global positioning.
Satellite Antenna - Parabolic dish that has a low noise block converter (LNBC) at the end of an arm protruding out in front of the dish, with a small antenna inside the LNBC.
Satellite Link - Communications path that includes a satellite or satellites.
Satellite Receiver - Demodulates communications information into audio, data, or video; the satellite dish receives RF transmissions, and sends the transmission to the receiver, which then tunes to the required channel received as part of the transmission.
Secondary Channel - Low speed channel established on a four wire circuit over which diagnostic or control information is passed. User data is passed on the primary, high-speed channels of the circuit.
Self Healing Alternate Route Protection (SHARP) - See Redundancy. Offered by local telephone companies over SONET networks; where a ring of fiber optic cable allows traffic to be rerouted in the event of a fiber cable being cut.
Serial Transmission - Method of data transmission in which each bit of information is sent sequentially on a single data channel. Transmission of a character or byte of data one bit at a time. Serial transmission is the normal transmission mode for data combinations. Contrasts with parallel transmission.
Series Circuit - A circuit with only one path for current through multiple loads.
Service Group - One or more access lines (DAL or T1) used to terminate calls from one or more 800 service numbers; a group of lines built as one trunk group from a DMS-250 switch. (A call placed to an 800 number routed to that trunk group can be completed on any of the lines in that trunk group.
Service Switching Point (SSP) - Computerized switches in a local exchange carrier (LEC) network that distinguish 800 calls from ordinary telephone calls. Communicates with the service control point (SCP) to obtain appropriate call routing instructions. Located either in a LEC end office or access tandem.
Short Haul - Circuit designed for use over distances less than 200 miles.
Signaling System #7 (SS7) - Sophisticated network signaling system that utilizes out of band signaling where signaling information is sent over a separate channel than the call itself; improves call processing set up times and frees circuits for voice, data, and video transmissions.
Simple Mail Transfer Protocol (SMTP) - Standard email application / interchange format allowing email applications to exchange messages between each other. Used in conjunction with Post Office Protocol (POP) and Multipurpose Internet Email Extensions (MIME) to provide TCP/IP email.
Simple Network Managed Protocol (SNMP) - Used in TCP/IP networks; a subprogram that monitors and controls network devices such as routers and hosts on a LAN or WAN; it enables users to troubleshoot, change/assign prot addresses, collect statistics, and manage configurations, performance, and security. Each device with an IP address is an agent, with the station/host/terminal monitoring agents on the network (called an SNMP Manager).
Single Mode Fiber - Alternative to multi mode fiber optic; single mode fiber has a smaller core but is best for longer distance applications such as SONET.
Smart Jack - Aka RJ68. Basically, an RJ45 with electronic components that allow it to be remotely placed in a loop back mode for testing purposes.
Span - One section of aerial wire.
Special Grade Network Trunk - Conditioned to parameters, by providing amplitude and delay equalization for handling special services such as medium speed data (600 to 2400 bps)
Specialized Automated Mail (SPAM) - Electronic junk mail, not to be confused with a meat by-product. Unrequested email messages that advertise products to email users.
Specialized Carrier - Company that provides value added communications facilities to limited geographical areas or for specific services.
Specialized Common Carrier (SCC) - Company that provides private line services (e.g., voice, telephone, data, fax).
Static Route - Network routing path configured and entered into a routing table by network administrators, taking precedence over dynamic routing protocols.
Standard Network Interface (SNI) - Aka Telephone Network Interface (TNI) or Network Interface (NI), terminating phone service at a customer location while providing lightning protection. One side of the SNI is for phone company use, the other side provides access for customer phone lines.
STM-1 - Building block for Synchronous Digital Hierarchy, with a bandwidth of 155.52 Mbps, and a format identical to STS-1 and the optical OC-1.
STS-3 - Electrical equivalent to OC-3, aka Level 2.
STS-3c - Physical layer transmission format known as STM1 outside the US and Japan; electrical equivlant of SONET OC-3.
Subscriber Loop - Pair of wires running from the telephone company central office to customer network interfaces.
Superframe Format - T1 framing format, consisting of 12 T1 frames at 193 bits each, transmitted in succession, allowing for maintenance and monitoring information to be sent along with the 24 DS0 channels.
Supergroup - Normally 60 voice channels, or 5 groups of 12 voice channels each occupying the frequency band 312 kHz to 552 kHz.
Switched Line - (1) One of a series of lines that can be interconnected to all other lines through a switching center. (2) Line on the public telephone network. Contrast with leased line.
Switching Office - Telephone company location housing a switch.
Symmetrical Digital Subscriber Line (SDSL) - Physical layer protocol, delivering high speed data networking over single pair copper phone lines, where the upstream and downstream data transmission rates are the same. Base transmission distance is 24,000 feet (about 5 miles), extendable to over 30,000 feet with repeaters, and beyond with fiber optic.
Synchronous Optical Network (SONET) - Broadband transport system over fiber optic, configured in a ring. If a fiber is cut, the ring allows it to reroute traffic with no service interruption. Becoming the CLEC's network construction mainstay, replacing copper twisted pair outside plant.
Synchronous Transfer Mode (STM) - Aka Broadband Integrated Services Digital Network, enabling the user to have a DS3, POTS line, or ISDN-BRI automatically, depending on the device accessing the line.
Synchronous Transfer Signal (STS) - In SONET networks, the electrical version of the SONET OC-1 level signal, where the optical signal is converted to electricity at one time so it can be demultiplexed and processed; transmitted node to node, or node to digital cross connect, or to DSX cross connect panels, via 50 ohm coax.