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saddle - A device for establishing the position of the raceway or raceways within the concrete relative to the screed line and for maintaining the spacing between the raceways.
safety grounding wand - Electrical protective device consisting of an insulated handle with a metal tip that is connected to an insulated cable with a large metal clip on the opposite end; the clip is connected first to a ground source and the metal tip is used to short any transient voltages left on a de-energized circuit.
safety margin - A power loss (dB) value used to assure optical fiber cable performance criteria will be satisfied over the life of the network. Includes expected losses in source power, splice losses, and wear and tear of connectors. See also loss budget.
safety plan - A plan prepared by a company and put in place before beginning any work operation, covering all safety issues likely to arise on a particular job site.
sag - 1. A decrease in nominal root mean square voltage or current lasting 0.5 cycles up to one minute. 2. The difference in height between an aerial cable mounting and the height of the cable above the surface at its lowest point (mid-span).
sally port - See interlock.
satellite closet - See telecommunications room.
satellite room - See telecommunications room.
S-band - The frequency spectrum from 1.55 to 3.9 GHz.
SC connector - See subscriber connector.
scalability - The ability of a network to grow without degradation of quality.
scanner - A device that verifies cabling segments for wiring scheme compliance (e.g., opens, shorts, crossed, reversed, split pairs). The device may also measure cabling segment length and performance.
scattering - The deflection of light by small particles or inhomogeneities whose size is similar to or smaller than the wavelength of light. See also Rayleigh scattering and Mie scattering.
scatternet - Consists of two or more piconets in a common area, where each piconet contains at least one Bluetooth® device that is part of two or more piconets.
schematic design - A design phase that follows preliminary planning and scope development and occurs prior to design development. (This phase typically takes the design to about 30 percent).
schematic diagram - A structural or procedural diagram used in association with telecommunications and electrical systems.
scintillation - In free space optics, describes the temporal and special variations in light intensities caused by differences of refractive index along the propagation path due to slight temperature variations among different air pockets.
scissor lift - Personnel lift composed of a working platform mounted on a large scissor jack.
scope of work (SoW) - A document that provides detailed statements and descriptions of the work content for the project requirements.
screed line - The line to which poured concrete is leveled.
screen - A thin metallic wrapping (e.g., aluminum foil) used to isolate cable pairs from interference. See also foil shield.
screened subnet - See lobby network.
screened twisted-pair (ScTP) cable - Cable made up of one or more pairs of twisted copper conductors with an overall foil shield and drain wire. The entire assembly is covered with an insulating sheath (cable jacket). Also called foil twisted-pair cable.
screened/foil twisted-pair (SIFTP) cable - A cable with one or more pairs having an overall braid screened cable with individual foil screened balanced twisted-pairs. This cable construction is common in category 7/class F cabling.
scribing tool - Used to scratch the surface of a fiber to facilitate a clean break in preparation for polishing.
scripting - The process of determining which configuration tasks can be performed unattended and then automating the process.
second generation (2G) mobile telephony - A worldwide implemented digital wireless voice technology that provides 9.6 to 14.4 kbls circuit-switched data service. 213 wireless systems may offer auxiliary services (e.g., fax, short message service). Most 213 protocols offer different levels of encryption
secondary power - Power operating at less than primary power voltage.
secondary power system - The power derived from the primary power lines through the use of distribution or stepdown transformers to reduce the primary line voltage to a lower secondary voltage suitable for commercial and residential service.
secondary protector - A secondary current and voltage protector installed in series with the indoor telecommunications cabling between the primary protector and the equipment. The secondary protector may provide over current and over voltage protection.
secondary test - After acceptance testing, additional tests that are conducted to diagnose a problem or verify the cabling to additional requirements.
secret key encryption - See private key encryption.
section throw - Splicing of a new section of cable at both ends into existing cable plant.
sectional drawing - Drawing as if a vertical cut was made through the materials indicating relationships, connections, and transitions.
SectionFormat - A guide published by the Construction Specifications Institute that describes the recommended uniform approach to organizing specifications text contained in a project manual by establishing a structure consisting of three primary parts: administrative (general), physical (products), and productive (execution).
sector antenna - An antenna used to provide coverage over only a sector of the azimuth range. Used on cellular towers.
secure server - A server that requires the use of a security protocol (e.g., securehypertext transfer protocol) during a communications session.
secured side - The area or side of an opening that is locked and requires a key card or other means to enter.
security (network) - Protection against unauthorized activities, generally requiring a combination of access controls, data integrity, and transaction confidentiality.
security and access control (SAC) - Equipment associated with systems used to monitor and control devices (e.g., card readers, door alarms, closed circuit television).
security management - The protection of network resources, including physical devices, operating systems, applications software, organizational data, and network operations.
security policy - The set of principles, rules, and practices that are used to implement security in an organization.
segment - 1. A portion of a network sharing a continuous length of cable. 2. A data unit created at the Transport layer of the Open Systems Interconnection Reference Model. It contains the data and control information necessary to transfer a message from one device to another on the same network. 3. An electrically continuous network created within a hub or other similar device. 4. A single broadcast domain or token-passing section. See also datagram and frame.
segmentation - The process of dividing a LAN into multiple independent segments to improve overall data transfer rates.
self-test - A feature of equipment to run programs at their start-up or at regular intervals to test its own operation.
sensitivity - 1. In optical fiber receivers, the minimum power required to achieve a specified bit error rate. See bit error rate. 2. In an electronic device (e.g., communications system receiver, detection device, PIN diode), the minimum input signal required to produce a specified output signal having a specified signal-to-noise ratio, or other specified criteria.
Sequential Couleur avec Memoire (SECAM) - An analog television display standard used primarily in France and former Soviet Union countries. SECAM scans the cathode ray tube 525x horizontally.
serial port profile (SPP) - The protocols and procedures that shall be used by devices using Bluetooth° for RS232 (or similar) serial cable emulation.
series circuit - A circuit where the devices are arranged in a chain, with only one path for the signal or current to follow.
Series 6 coaxial cable - Having a center conductor measuring approximately 18 AWG [1.0 mm (0.039 in)], it supports similar applications as Series 11 coaxial cable; however, over a shorter distance due to increased insertion loss (attenuation) characteristics. Typically used for drop cabling. Formerly called RG-6.
Series 11 coaxial cable - Having a center conductor measuring approximately 14 AWG [1.6 mm (0.063 in)], it supports similar applications as Series 6 coaxial cable; however, over a greater distance due to reduced insertion loss (attenuation) characteristics. Typically used for backbone cabling. Formerly called RG-11.
server - A network device that combines hardware and software to provide and manage shared services and resources on the network.
service clearance - The space encompassing the equipment, or unit, that is required to permit proper working room for operating, inspecting, and servicing equipment.
service discovery profile (SDP) - Discovers from other Bluetooth6 devices such as printers or fax machines, Bluetooth services such as cordless telephony, file transfer profile, or headset profile.
service entrance - See entrance facility (telecommunications).
service equipment (power) - The necessary equipment, usually consisting of a circuit breaker or switch and fuses, and their accessories, located near the point of entrance of supply conductors to a building or other structure, or an otherwise defined area, and intended to constitute the main control and means of cutoff of the electrical supply.
service fitting - An outlet box to house the connections for telecommunications at the user work area. See also insert.
service loop - A surplus of cable, typically located at or near the point of termination to facilitate potential future changes.
service provider (SP) - The operator of any service (e.g., application programming interfaces) that furnishes telecommunications content (transmissions) delivered over access provider facilities. See also access provider (AP).
service set identifier (SSID) - A character string used for identification of a service set. Service sets must have identical SSIDs to establish radio contact. See basic service set and independent basic service set.
service wire - An underground or aerial cable that connects a serving outdoor terminal to a building or structure.
servo - A transducer that converts coded electrical signals into precise angular or linear motion.
Session layer - The Open Systems Interconnection Reference Model layer responsible for providing services used to organize, synchronize, and manage a given message exchange between network devices. Also called Layer 5.
setscrew coupling - Couplings that are placed over the ends of conduit with little or no friction. Once the end of the conduit is seated into the coupling, two screws are tightened on the outside of the coupling, causing the coupling to become firmly attached to the conduit.
shadowing - See disk mirroring and mirroring.
shallow room - An enclosed space for housing cable terminations, crossconnect cabling, and telecommunications equipment.
shared tenant service (STS) - Consolidates individual-line subscribers using a common premises switch.
shear lock magnetic lock - A modification of the direct hold magnetic lock that utilizes both magnetic and physical properties for locking. The electric magnet's lock body is mortised into the door's frame and the armature is mortised into the door edge. Indentations in the armature receive protrusions in the lock body.
sheath - See cable sheath.
sheath (cable) loop diversity - A type of loop diversity that assigns circuits among different sheaths or cables.
shell - A software-controlled interface between a user and an operating system. The shell software examines commands and user interaction for access to remote resources, processing the requests via the operating system.
shield - A metallic layer (e.g., copper braids, metal foils, solid tubing) placed around a conductor or group of conductors.
shield coverage - The percentage of a conductor's surface area actually covered by shielding material.
shielded enclosure cabinet - A metal electronics cabinet constructed with welded seams and conductive gaskets on the doors that serve as an effective shield against electromagnetic radiation.
shielded twisted-pair (STP) cable - Cable made up of multiple twisted copper pairs with an additional metallic shield covering each individual pair. The entire structure is covered with an overall shield or braid and an insulating sheath (cable jacket).
shield effectiveness - See shielding effectiveness.
shielding effectiveness - Expressed in terms of a cable's transfer impedance shielding effectiveness, it is the ratio of the voltage applied to the shield to the current flowing through the shield.
shop drawing - These drawings may be prepared by the contractor, subcontractor, or material/equipment supplier, and show how a particular aspect of the work is to be fabricated or installed.
short - A low-resistance connection between two conducting materials.
short circuit - An accidentally established low-resistance connection between two points in an electric circuit.
shorting bar - Used to loop a signal between two discrete contacts.
shorting plug - A device to create a direct connect between two or more conductors at one end of a cable for test purposes.
short message service (SMS) - Similar to e-mail store and forward, SMS is a service for sending short text messages (up to 160 characters) to mobile devices (phones, pagers) via SMS centers.
short wavelength (SW) - See wavelength.
shrouded dish - Used where interference
to/from other systems on the same frequency and in the same area must be avoided.
sigma - The measurement of a process in producing defect-free design, product, delivery, and service, with a defect being anything that results in customer dissatisfaction.
signal encoding - The conversion of data into a form suitable for transmission over a medium.
signal fading - Parts of a signal branching into different paths from the transmitter to the receiver due to obstructions.
signal generator - Test equipment that generates a distinctive tone(s) that is placed on a cable pair for identification purposes. Also called a tone generator.
signaling - The central information or supervisory information provided by a network to facilitate circuit setup and disconnection. One example of signaling is the process used to transfer a sequence of bits over a communications medium.
signaling line circuit (SLC) - A circuit or path between any combination of circuit interfaces, control units, or transmitters over which multiple system input signals or output signals, or both, are carried.
Signaling System 7 (SS7) - A separate packet network that provides out-ofband signaling for the public switched telephone network.
signal quality error (SQE) - Transmission sent by a transceiver back to the controller to let the controller know whether the collision circuitry is functional. Also called a heartbeat. (Cisco Systems, Inc.)
signal splitters - Signal splitters are used to connect more than one antenna to a single radio.
signal strength - In a communications system, the signal power or intensity at a specified point and with respect to a specified reference level.
signal-to-noise ratio (SNR) - The ratio between the amount of signal power at the receiver input and the detected noise in a given communications system, expressed in decibels.
signature verification - A biometric method using a person's signature characteristics (writing speed, pen pressure, shape of loops, etc.) to identify that person.
simplex - A process during which signals are transmitted in only one direction; one station is the transmitter and the other is the receiver.
simplex signaling - A unidirectional signaling method in which data transfer can take place in only one direction, with no capabilities to change directions. See also dualduplex signaling, full-duplex signaling, and half-duplex signaling.
sine wave - A sinusoidal wave that varies periodically from zero to a maximum, back through zero to a minimum, and back to zero.
single attachment - A device in an optical fiber distributed data interface network that has a single transmit/receive connection to the primary ring.
single-attachment concentrator (SAC) - A fiber distributed data interface concentrator that has a single transmit/receive connection to the primary ring path only. Contrast with dual-attachment concentrator.
single-attachment station (SAS) - A fiber distributed data interface Class B station with a single transmit/receive connection to the primary ring path only. Contrast with dual-attachment station.
single-gang box - A device used to house information transport systems or electrical cabling for the purpose of attaching a faceplate or cover that houses connectors for the interconnection of equipment.
singlemode optical fiber - Optical fiber with a relatively small core diameter of 8-9 micron (micrometers) and a cladding diameter of 125 micron; lightwave propagation is restricted to a single path, or mode, in singlemode optical fiber.
single-point ground (SPG) terminal - A ground connecting point for connecting communications equipment and raceways to the building's grounding system.
single sideband modulation - A variation of the amplitude modulation technique where the carrier and one half of the sideband is suppressed. This effectively halves the bandwidth and power requirements of a radio frequency transmission.
single sign-on (SSO) - A system that makes it possible to store all identity information (e.g., various user names and passwords for each user and administrator) in a centralized database on the network.
site drawing - A two-dimensional graphic representation of the land and any exterior pathways that are being installed upon which a construction project will take place.
site survey - A process used to identify the characteristics of an environment impacting the installation of network components. Required for the design of any network.
skin effect - The tendency of current to flow only near the surface of a conductor. This effect becomes more pronounced at higher frequencies.
sky wave - A radio wave that travels upward from the antenna. A sky wave may be reflected to Earth by the ionosphere, troposphere, or stratosphere.
slab - See floor slab.
slab on grade - Concrete floor placed directly on soil, without a basement or crawl space.
stave - 1. A Bluetooth wireless device that communicates with a master to form a piconet. 2. Any secondary device that is controlled by a primary device, called the master.
sleeve - An opening, usually circular, through the wall, ceiling, or floor to allow the passage of cables.
slip sleeve - An oversized conduit that moves easily along an inner conduit and covers a gap or missing part of the smaller conduit.
Slot - An opening through a wall, floor, or ceiling, usually rectangular, to allow the passage of cables.
slotted antenna - A highly directional antenna. It utilizes slots in wave guides to radiate a signal in a single direction. It also can be used with solid conductors as a complementary dipole antenna.
slotted array - A type of very rigid antenna. Can be either fixed or rotating. It is used on aircraft, trains, radar, and cellular base stations.
slow frequency hopping - A frequencyhopping spread spectrum technique in which the frequency is changed once every 4.615 millisecond.
small computer system interface (SCSI) - A set of American National Standards Institute standard electronic interfaces that allows computers to communicate with peripheral hardware (e.g., disk drives, tape drives, CD-ROM drives, printers, scanners).
small form factor (SFF) connector - A connector that consists of two optical fibers secured in a plug approximately the size of an 8-position modular jack. An alternative type of optical fiber connector allowed under ANSI/TIA/EIA 568-B.3.
smart antenna - Combines multiple antenna elements with an active electronics signal processing capability to optimize and adapt the antenna pattern dynamically in response to the signal environment.
smart appliances - Products that include some processing power within themselves and have the ability to send or receive data or control messages to/from another product. All use some digital control to automate some product function and some send control messages, but most cannot both receive and send information.
smart card - A card with a built-in integrated circuit chip. This gives the card microprocessor memory and intelligence to use for storing data.
solar interference - Intense levels of direct sunlight that interfere with signal reception in free space optical systems.
solid conductor cable - A cable composed of a single gauge conductor wrapped in an insulating coating. Contrast with stranded conductor cable.
solid-state protector - Arc protection (arrestor) devices based on high-power semiconductor technology that do not deteriorate with age below a rated maximum surge current.
SONET node - See synchronous optical network (SONET) node.
sound level meter - Instrument used to measure actual pressure created by a sound.
sound pressure level (SPL) - The actual air pressure created by a sound as measured by a sound level meter.
source - The means (usually light-emitting diode or laser) used to convert an electrical information-carrying signal into a corresponding optical signal for transmission by an optical waveguide.
source address table (SAT) - The internal database used by a bridge to track the medium access control addresses of devices connected to each port of the bridge.
space (telecommunications) - An area used for housing the installation and termination of telecommunications equipment and cable.
space diversity - A wireless receiver configuration that utilizes two antennas located some distance apart in order to minimize the effects of certain types of fading (e.g., multipath). Since some types of fading are extremely localized, space diversity improves reliability because the second antenna may continue receiving the desired signal even when the first antenna is experiencing a fade.
smart environment - A smart environment employs pervasive embedded computation systems to collect sensory data from the real world, assess and evaluate the resulting information, interact with human users, and perform and facilitate alarm, decision-making, and control functions. Smart environments can exist in houses, vehicles, buildings, and campuses and include the use of communications networks, sensor devices, computer hardware, and software. The word "environment" refers to the location where the employed systems collect data and operate to adapt accordingly.
snake rod - A telescoping pole used to route horizontal cable above dropped ceilings.
sneak current - A foreign current flowing through terminal wiring and equipment that is driven by a voltage that is too low to cause the overvoltage protector to operate.
sneak current protection - The use of devices to protect against sneak currents either by interrupting the current (sneak current fuses) or grounding the conductor (heat coils).
socket - 1. A method of associating a program or process with a software address so they can communicate with other programs or processes. 2. A hardware defined socket connection is the combination of a data communication device address and the logical channel (port) number.
soft handoff - A cellular signal that is controlled by multiple cells before disconnecting and being handed off from the previous controlling cell (make-beforebreak).
softphone - Internet protocol telephone software installed on desktop, laptop, or handheld computers.
softwired - The type of power cord used to connect uninterruptible power supplies with plug-in type power receptacles.
space wave - A radio wave that is not reflected back to earth and continues into outer space. These radio waves above 30 MHz have shorter wavelengths, which penetrate the ionosphere and continue on into outer space. Also called direct waves.
spade lug - A U-shaped metal connector that is soldered or crimped to a wire, used for connection to a terminal post.
span - The length between two support points. In aerial plant, the span is the space between two poles or building connection points.
span guy - Guying installed across a span placed on straight pole lines to reinforce them against excess tension placed on them by severe weather conditions. Also called a line guy or pole-to-pole.
spanning tree - An operation used by bridges to create a logical topology that connects all of the bridge-equipped networks to be interlinked. It ensures that no path loops exist on the internetwork.
spanning tree algorithm (STA) - An algorithm used by bridges to create a logical topology that connects all of the bridgeequipped networks to be interlinked. It ensures that no path loops exist on the internetwork.
spatial, resolution - Setting on an optical time domain reflectometer to determine how close individual data points are spaced in time and distance.
speaker - A device that changes electrical signals into sounds.
specialized common carrier - A common carrier offering a limited type of service or serving a limited market.
specification - An essential technical requirement for items, materials, or services, including the procedures to be used to determine whether the requirement has been met.
spectral mask - A radio transmitter's radiated power confined to a band of frequencies through the use of a bandpass filter.
spectrum - A range of frequencies (electromagnetic, optical, and radio) that comprises a signal or defines a communications channel.
spike - An instantaneous surge of energy. spine cable tray Open tray with a central rigid spine with cable support ribs along the length at 90-degree angles.
splayed - Sloped, slanted, or spread outward. Splayed maintenance hole duct entrances are placed toward the outward sides of an entrance wall rather than placed in the center of the entrance wall.
splice - 1. A joining of conductors meant to be permanent. (TIA) 2. A device that joins conducting or transmitting media. See also straight splice.
splice (ground wire) - A method where ground wire is extended .byjoining together two or more separate sections by fusing or mechanical connectors.
splice bank - Placement of 25-pair modules in a symmetrically spaced configuration within a splice enclosure.
splice box - A box, located in a pathway run, intended to house a cable splice.
splice case - A metal or plastic housing with a semi-cylindrical cavity used in identical pairs to clamp around a cable splice to provide a closure.
splice closure - A device used to protect a splice. (TIA) See also splice case.
splice tray - A container used to organize and protect optical fiber splices, as well as a means for storing fiber slack.
splicing - The act of joining copper conductors or optical fiber strands.
splicing head - A section of a splicing rig that supports the crimp head. It can be either single or dual.
splicing rig - A specific manufacturer's tool kit for terminating modular connectors.
split grip - A wire mesh grip that is open on one side and, when attached to cable facilitates the physical support of cable.
split pair - Transposition of two conductors of separate pairs.
splitter - A network device that provides signals to a number of outputs, which are individually matched and isolated from each other. A passive device used to divide the signal into two or more outputs.
spoofing - 1. The interception, alteration, and retransmission of data in such a way as to mislead the recipient. 2. An attempt to gain access to an automated information system by posing as an authorized user.
spool - 1. A combination of hardware and software commonly used by print servers to redirect requests destined for a printer. 2. Cylindrical containers of cable. See cable reel. 3. A cylindrical guide, typically used for routing jumpers, cross-connects, and patch cords.
spooling - The use of secondary or auxiliary storage as a buffer to temporarily store data until it can be queued for processing (e.g., print spooling)
spread spectrum - A radio transmission technology that distributes the transmitted signal over multiple frequencies within the assigned frequency band to increase the overall immunity of the signal to noise and prevent message interception.
spreading ratio - The number of bits used in the chipping sequence to represent a message bit.
spurious emissions - Emission on a frequency or frequencies that are outside the necessary bandwidth and the level of that may be reduced without affecting the corresponding transmission of information.
spurious rejection - The ability of a receiver to reject emission on a frequency or frequencies which are outside the necessary bandwidth and the level of which may be reduced without affecting the corresponding transmission of information.
stackable hub - Multiple hubs that are in close proximity, capable of being connected to each other using a short length of specialized cable assembly, and functioning together as a single unit. See also hub.
staging area - An area at a job site where the bulk of the materials and tools is kept and distributed.
stand-alone cell - A wireless cell with a single access point and no connectivity to any other network.
standard - A collection of requirements that encompass properties of components and systems that are intended to ensure an accepted degree of functionality and longevity. (ATIS)
standard network interface (SNI) - A device that serves as a demarcation point between the local exchange carrier and the customer. Usually a modular jack with some type of mounting forthe modularjack.
standby monitor - A device on a token ring LAN that monitors the active monitor. Its function during normal ring operations is to verify that an active monitor is operating on the ring.
standing wave ratio - The ratio of the amplitude of a standing wave at an antinode to the amplitude at a node. A normalized measurement or calculation conducted in radio frequency systems useful for determining the amount of power reflected back to a source versus that delivered to the load.
star coupler - An optical component that allows emulation of a bus topology in an optical fiber system.
star topology - A network topology in which services are distributed from or through a central point.
start bit - A bit used in asynchronous communications to indicate the beginning of a character. See also stop bit.
star-wired ring - Physical star configured as a logical ring. Also called a collapsed ring through a hub that performs all appropriate routing operations.
stateful inspection - Firewall software processes used to identify suspicious network communications.
static dissipaters - This device is an array that dissipates static charges by providing a low resistance route for static ground charge to reach the atmosphere, thus preventing a buildup of the ground charge to the value necessary to trigger a strike.
static grounding wrist strap - A device used to dissipate the built-up static charge from an individual to the ground to avoid damaging sensitive circuits.
station - 1. A device used by an individual to access network services. 2. An input or output point in a communications system (e.g., telephone, computer, fire alarm station). See also local station and remote station.
station cabling - See horizontal cabling.
station conductor - A wire that tetminates at the equipment side of the protector.
station cord - See work area cable (cord).
station equipment - See customer premises equipment and work station.
station fuse - An overcurrent device used at the customer's premises.
station location - Telephone or computer location.
steerablelpolar mount - Antenna support structure that steers the reflector.
step by step (SxS) - An electromechanical telephone switching system.
step-index fiber - An optical fiber, either multimode or singlemode, in which the core refractive index is uniform throughout so that a sharp step in refractive index occurs at the core-to-cladding interface.
stick - Slang term used to describe a section of conduit.
stipulated sum - See lump sum.
stop bit - A bit used in asynchronous communications to indicate the end of a character. See also start bit.
storage area network (SAN) - A specialized high-speed network dedicated to the transport of data between storage devices and servers.
storage virtualization - See virtualization.
store-and-forward - 1. The recording, processing, storage, transmission, and viewing of an activity after it has occurred. Contrast with real-time. 2. A switching method in which messages are stored as they are received, fully checked for errors, and then forwarded. See also cut-through and modified cutthrough.
STP-A - An IBM designed, shielded twistedpair cable consisting of two individually shielded 22 AWG [0.64 mm (0.025 in)] conductor pairs, with an overall shield capable of supporting transmission to 300 MHz.
straight splice - A splice in which one conductor or optical fiber strand is spliced from opposite directions.
straight tip (ST) connector - A type of optical fiber connector identified by its bayonet mating mechanism. Also called BFOC/2.5 (bayonet fiber optic connector with 2.5 mm [0.10 in] ferrule).
strand - 1. A single string of wire used to make up a larger wire or cable by twisting a number of strands together. Galvanized steel stranded cable is used as support strand and guy wire. 2. A single unit of optical fiber within a cable.
stranded cable - A cable with individual conductors composed of groups of wires twisted together.
stranded conductor cable - A cable composed of a bundle of smaller gauge wires wrapped in a single insulating coating. Contrast with solid conductor cable.
strand identifier - A clamp-on unit that inserts a microbend into optical fiber cable and detects light escaping from the fiber.
strand vise - A gripping device used with a hoist for the tensioning of a strand.
streaming - A group of technologies developed to enable the transfer of multimedia content over a network for immediate play at the receiving device before the entire file has been downloaded.
strength member - That part of an optical fiber cable composed of aramid yarn, steel strands, fiberglass filaments, or fiberglass-reinforced epoxy composite rod that increases the tensile strength of the cable.
stress detector - A device that detects the stress in beams when walking above or near.the detector.
striping - A data storage technique in which the content of a given file to be stored is divided and placed on multiple hard disk drives for faster retrieval and improved fault tolerance.
stripping in token ring - The process of a sending device removing the frames it has previously transmitted from the ring.
stroke factor - The number of lightning strokes to ground per unit area for each thunderstorm day (obtained by statistical studies).
structural return loss (SRL) - Ratio in dB of the test signal power and the reflected signal power due to impedance variations in the cable.
structured cabling system (SCS) - The complete collective configuration of telecommunications cabling and associated hardware at a given location. stub-out See conduit stub-out. stub-up See conduit stub-u
subbase - A layer of specified material between the pavement and the subgrade.
subduct - See innerduct.
submittal - Information, documentation, or samples that a contractor may be requested to submit to the design team for review and approval before the commencement of work.
subnet - See subnetwork.
subnet mask - A fictitious (nonusable) Internet protocol (IP) address whose only function is to identify the number of bits, within a 32 bit IP address field, that have been borrowed from the host address to identify a subnet. This mask is used by Layer 3 devices to identify subnets.
subnetting - The process of dividing a single broadcast domain into two or more smaller broadcast domains by modifying Network layer address assignments. See also subnetwork.
subnetwork - A single broadcast domain in a network that is made up of multiple broadcast domains.
subscriber connector (SC) - The optical fiber SC connector (SCFOC/2.5) has a square front profile with push-pull latching mechanism maintaining the polarity of duplex cables.
subscriber identity module (SIM) card - A smart card inserted into the Global System for Mobile Communications mobile station containing customer information.
subscriber line - A communications channel from a switching center or an individual message distribution point to the user terminal.
subscription limit - The number of users that a network is designated to economically accommodate, under normal operating conditions, without degrading network services.
substitution - A replacement or alternation of material or process called for in the design documents.
superhigh frequency (SHF) - Frequencies in the range of 3 GHz to 30 GHz
supernetting - The combining of two separate but contiguous Class C Internet protocol networks into a larger group connected to a single, common interface (generally a routing device).
supervisory control and data acquisition (SCADA) - SCADA systems are used in industry and by public utilities (e.g., pipelines, electric utility grids) to monitor and control plant status and provide logging facilities that are often scattered over wide geographic areas. SCADA systems are highly configurable and traditionally use standard telephone lines to propagate their data. Public utilities are starting to utilize these systems for the integration and transmission of voice, data, and security systems.
supplementary - The way to provide additional conditions to a contract that may add, delete, or modify the general conditions.
support strand (messenger) - A strength element used to carry the weight of the telecommunications cable.
surety bond - A bond that ensures a respondent (bidder) to a request for quote (RFQ) is sincerely interested in performing the project and has responded accurately to the RFQ specifications.
surf control - A security process used to prevent internal network users from accessing unauthorized Web sites. Also called Internet access management.
surface fitting - Surface-mounted service fitting. See also service fitting.
surface-mounted raceway - Plastic or metallic raceway that is installed on the surface of a wall, floor, or ceiling that provides a protective pathway for cables and/or power from public access.
surge arrester - 1. A protective device for limiting surge voltages by discharging or bypassing surge current, and it also prevents continued flow of follow current while remaining capable of repeating these functions. (NEC) 2. Electrical or lightning arrestors designed to protect equipment between the power source and the equipment being protected.
surge protective device - See surge arrester.
survivability - The ability of the network to function after minor or major disruption.
susceptibility (electromagnetic) - The inability of a device, equipment, or system to resist an electromagnetic disturbance.
suspended ceiling - A ceiling that creates an area or space between the ceiling material and the structure above.
sweep test - A measurement performed where a range of signals of different frequencies are injected into a radio frequency system in order to measure the resulting performance.
sweep - Bend that has a gentle arc rather than a sharp bend.
swell - An increase in the nominal root mean square voltage or current lasting from 0.5 cycles to one minute.
swing floor phasing - The act of removing personnel and property from one location to another in order to facilitate renovation of the space vacated.
swingset - See bullwheel.
switch - 1. A network access device that provides a centralized point for LAN communications, media connections, and management activities where each switch port represents a separate communications channel. Sometimes referred to as a multiport bridge. See also bridge. 2. A voice communications device that utilizes switching technology to establish and terminate calls.
switch fabric - Multiple switches used to link storage area network storage devices to server clusters.
switch latency - The amount of time it takes for an incoming message to be inspected, processed, and forwarded through a switch.
switch matrix - Connections that link each port to every other port. Also called a backplane.
switched virtual circuit (SVC) - A virtual circuit created on an as-needed basis. It is a temporary connection lasting only as long as the connected devices are communicating. Contrast with permanent virtual circuit.
switching - 1. Networking protocol in which a station sends a message to a hub, which then routes the message to the specified destination station. 2. Establishing a direct signal path from one device to another.
symmetric key cryptography - See private key encryption.
symmetrical pair - A balanced transmission line, in a multipair cable, having equal conductor resistances per unit length, equal impedances from each conductor to earth, and equal impedances to other lines.
synchronization profile - Commonly used in a personal area network to update calendar and scheduling information between laptop, personal digital assistant (PDA), and mobile phone. Once the PDA device comes within range, the synchronization can automatically occur.
synchronous communication - See synchronous signaling.
synchronous connection oriented (SCO) link - A point-to-point link between the master device and one slave device, used primarily for synchronous voice traffic.
synchronous optical network (SONET) node - The interface to a SONET network.
synchronous optical (SONET) - A scalable transport technology designed to provide a uniform, consistent method of transferring data, by using an optical fiber transmission infrastructure network.
synchronous signaling - A form of signaling in which no start and stop bits are used. Each data character is coded as a string of bits and the sending and receiving devices are synchronized with each other, using a common clock. See also asynchronous signaling and isochronous signaling.
synchronous transmission - Transfer of data using synchronous signaling.
system integrity - That condition of a system wherein its mandated operational and technical parameters are within the prescribed limits.
system reliability - The probability that a system, including all hardware, firmware, and software, will satisfactorily perform the task for which it was designed or intended, for a specified time and in a specified environment.
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