Cache - Generally, a place to temporarily store something. Regarding computers and telecommunications, it is a place where data is temporarily stored during transmission.
Call - This is a connection between two or more users with the intent of exchanging information.
Call Back - This is a security method with which a user calls into a system and requests to be called back by the system at a particular, predetermined number.
Caller - Anyone who makes a call.
Caller ID - The service that allows someone being called to see the caller's name and phone number.
Call Progress - This is the status of the telephone line. It can be busy, ringing, not ringing, etc.
Call Waiting - This is a service that tells you if someone is trying to call you when you are already using the line (i.e., talking with someone else).
Capacitor - This is an electronic device for storing electric charge.
Capture Effect - This effect occurs when two signals are received that are the same (or nearly the same) frequency. The stronger signal will appear in the output.
C-Band - The portion of the electromagnetic spectrum allotted for satellite transmission; it is the 4 to 8 GHz frequency transmission range. Specifically, the 3.7 to 4.2 GHz band is used as the downlink, and the 5.925 to 6.425 GHz band serves as the uplink.
Card - This term refers to a computer peripheral that can be connected internally (i.e., directly), without any cables, to a computer, such as a modem.
Caret - This is the character "^".
Carrier - This term refers to: (1) a company, such as a local telephone company, that provides circuits dedicated to communication, and (2) an electrical signal capable of being modulated to carry information.
Carrier Detect (CD) - This is a light on most modems that signifies, when lit, that the modem is connected.
Carrier Frequency - The main frequency on which data, a voice, or video signal is sent. Common microwave and satellite communications transmitters operate in the band from one to fourteen GHz.
Carrier Signal - The basic radio, television, or telephony center of a frequency transmission signal.
Cassegrain Antenna - An antenna that places a subreflector at the focal point to reflect energy to or from a feed located at the apex of the main reflector.
CB - This stands for Citizen's Band and is low-power (up to 4 Watts), public radio that does not require FCC approval.
CD - See Carrier Detect.
CDMA - This stands for Code Division Multiple Access and refers to a multiple-access scheme where stations use wide-spectrum modulations and orthogonal codes to reduce the chance of interfering with each other.
Central Office (CO) - This is a place where lines are joined to switching equipment (which control connections).
Channel - A frequency band, 6 MHz wide in the US, in which a specific broadcast signal is transmitted. Channel frequencies are determined in the US by the Federal Communications Commission (FCC).
Character - This is a letter, numeral, or symbol.
Characters per Second (CPS) - This is the number of characters that can be sent over the phone lines in 1 second.
Chat - A mode that allows two or more people to communicate with each other in real time over a network using modems.
Checksum - This is the sum of a group of data items that is used for error checking. Received information packets must have the same number of bits present during the initial transmission.
Chip - This is the physical structure of an integrated circuit.
Circuit - This is an electrical device that provides a path for electrical current to flow, or more generally, it is a journey or route all the way around a particular place or area.
Circular Polarization - Some satellites transmit both right-hand rotating and left-hand rotating signals simultaneously on the same frequency. This technique effectively doubles the channel carrying capacity of the satellite.
City Code - Some foreign countries require you to dial a city code before the phone number you are trying to reach.
Clamp - A circuit that removes the energy dispersal signal component from the video waveform.
Clarke Orbit - This is the circular orbit in space 22,237 miles from the surface of the earth at which geosynchronous satellites are placed to revolve around the earth. It is named after Arthur C. Clarke, who first postulated its existence. Satellites in these orbits move at speeds that cause their angular velocity to match the angular rate of the rotation of the earth, causing them to appear stationary when viewed from a particular point on Earth.
Clear to Send (CTS) - This is when a receiving modem tells the calling modem.
C/N (Carrier to Noise Ratio) - This is the carrier-to-noise-ratio, which is the ratio of the received carrier power to the noise power in a given bandwidth; it is expressed in decibels (dB), which is a logarithmic scale.
CO - See central office.
Codec - A coder/decoder system for transmitting digital data.
Color Subcarrier - A particular subcarrier that is added to the main video signal; its purpose is to convey the color information.
Columns - A column contains an item of data within a row.
Command - This is a software instruction that causes a specific job to be done.
Command Buffer - This is a memory place where commands are store temporarily.
Command Set - A collection of commands. (See Command.)
Commercial Internet (.com) - This is the part of the internet that is provided by commercial services, allowing business usage of the internet.
Common Carrier - Any organization which operates communications circuits used by other people. Common carriers include the telephone companies as well as communications satellite owners, AT&T and others.
Communication Channel - This is a type of circuit, and it is a two-way information pathway.
Communications Protocol - These are procedures used to ensure a standardized transmission occurs.
Compatible - When one object can be used interchangeably with another.
Composite Baseband - The unclamped and unfiltered output of the satellite receiver's demodulator circuit. It contains all of the video information as well as all transmitted subcarriers, such as the color subcarrier.
Compression - This occurs when information is reduced in size but all of the necessary information is retained.
Compression Ratio - This is the ratio of the original size of data that is sent to the compressed size.
Computer Network - See Network.
Configuration - This is the software or hardware arrangements that define a computer (or telecom system) and determine what actions will be carried out (and how).
Connected - This means you are online.
Connect Speed - Modem speed in bps.
Connection - A electrical pathway between telephones or similar devices.
Control Channel - With a cellular telephone system there are a few channels that allow the base stations to transmit information to the cell phones in its area.
Conus - This stands for Contiguous United States.
Copyright - This protects an author's work from being directly copied by another.
Country Code - This is the standardized code that designates a certain country.
Coverage Area - A geographical area that is defined by the coverage of a particular satellite.
CPS - See characters per second.
Crash - This is the complete failure of software or hardware operation. The only available option is to restart from an initial condition.
CRC - See Cyclic Redundancy Check.
Cross Modulation - A form of distortion in which modulation from one or more carriers' signals is imposed on another carrier's signal.
CRT - This stands for Cathode Ray Tub, and is a glass device used in video displays (e.g. televisions).
C/T - Carrier-to-noise-temperature ratio.
CTRL - This is the abbreviation for the ConTRoL key-command.
CTS - See Clear to Send.
Cursor - This is the particular marker that points out the next place the text will next appear on your screen.
Cyclic Redundancy Check (CRC) - This is a common process that is used to validate the integrity of a block of data.
補(bǔ)充：
Client - A program or computer that is used to contact and obtain data from another program or computer, referred to as the server.
CLEC - Competitive Local Exchange Carrier. Deregulated local telephone companies resulting from the Telecommunications Act of 1996 that are competing for local exchange service, as well as for long distance and Internet service.
CO - Central Office. A telephone company’s building where subscribers’ lines are joined to the switching equipment to connect calls.
Cookie - A small data file sent to a Web browser by a Web server that is used to record a user's activities on a Web site. For instance, when you buy items from a site and place them in a "shopping cart," that information is stored in a cookie. When the browser requests additional files, the cookie information is sent back to the server. Cookies can remember other types of information, such as your password, so you don't have to re-enter it every time you visit a site. They also retain your preferences, so when return to a site, you can enjoy customized information. Cookies cannot read any other information stored in your computer.
Connectivity - The technical communications link between a computer system and the Internet.
Cramming – An illegal practice in which customers are billed for additional telephone features they didn't’t order.
CSSR – Customer Sales and Service Representative. These TDS Telecom employees work in the sales and service offices of our local operating companies. They answer customer questions, market services, and handle payments.
CST – Customer Service Technician. These TDS Telecom employees work in our local operating companies and provide installation and repair service for our customers.
CAB
Carrier Access Business
Cable
A cable is a group of metallic conductors or optical fibers that are bound together, usually with a protective sheath, a strength member, and insulation between individual conductors/fibers and for the entire group.
CABS
Carrier Access Billing System - We fully explain what a Carrier Access Billing System is on this website. See the main page of this website for more information.
CALC
customer access line charges
CAP
competitive access provider
Carrier
A carrier is a local (intra-LATA) or long distance (inter-LATA) telecommunications service providing organization. A waveform, pulsed or continuous, that is modulated by another information bearing waveform.
Carrier System
A carrier system is a transmission system for transmitting one or more channels of information by processing and converting to a form suitable for the transmission medium used. Carrier systems are classified as either analog carrier systems or digital carrier systems.
CBR
continuous bit rate
CCIS
common-channel interoffice signaling
CCITT
CCITT is the International Consultative Committee for Telephone and Telegraph, a consultative committee to the International Telecommunications Union (ITU) which recommend international standards for telephone and telegraph services and facilities to aid international connectivity and interoperability.
CCSA
common-control switching arrangement
CCS
centi-call seconds or common-channel signaling
CDMA
code division multiple access
Cell Relay
Call relay is the process of transferring data in the form of fixed length packets called cells. Cell relay is used in high-bandwidth, low-delay, packet-like switching and multiplexing techniques. The objective is to develop a single multiplexing/switching mechanism for dividing up usable capacity (bandwidth) in a l-manner that supports its allocation to both isochronous (e.g., voice and video traffic) as well as packet data communications services. Standards groups have debated the optimum cell size. Small cells favor low delay for isochronous applications but involve a higher header to user information overhead penalty than would be needed for most data applications. The current CCITT specification for BISDN is for a 53-byte cell which includes a 5- byte header and a 48-byte payload.
Centi Call Seconds (CCS)
CCS is a unit of the average traffic intensity of a facility during a period of time, a CCS is 100 call seconds of traffic during one hour. Therefore a single traffic source, e.g., one call that generates traffic 100% of the time produces 36 CCS of traffic per hour, i.e., 3600 seconds of traffic every 3600 seconds. An equivalent amount of traffic could also be generated by 10 sources that only generate traffic 10% of the time. That is, 10 sources of traffic generating 3.6 CCS each, contributes the same total traffic as a single 36 CCS traffic source. An alternative measure for traffic is erlangs where 1 erlang equals 36 CCS.
CENTRal EXchange (Centrex)
Centrex is a LEC-provided switching service for business customers that permits station-to-station dialing, listed directory number service, direct inward dialing and station number identification on outgoing calls. The switching functions are usually performed in a central office. Digital Centrex offers the advanced features of fourth generation PBXs, without the need to purchase or lease equipment and, in most cases, eliminates the need for floor space, electrical prime power and heating, ventilation and air conditioning.
Central Offices (CO)
A central office is a telephone company building in which network equipment such as switches are installed.
Channel
A channel is a single communications path in a transmission medium connecting two or more points in a network, each path being separated by some means; e.g., spatial or multiplex separation, such as frequency or time division multiplexing. "Channel" and "circuit" are often used interchangeably, however circuit can also describe a physical configuration of equipment that provides a network transmission capability for multiple channels. The characteristics of channels and circuits are determined by the network equipment and media used to support them.
Channel Service Unit (CSU)
Channel Service Units (CSUs) and Data Service Units (DSUs) are required to connect digital customer premises equipment (CPE) to carrier networks. A CSU is network channel terminating equipment (NCTE) attaching as CPE to telephone company's digital circuits, and protecting the network from harm. Other CSU functions include line conditioning and equalization, error control (e.g., bipolar signal violations), and the logical ability to respond to local and network loop back circuit testing commands. See Data Service Units (DSU).
Circuit Associated Signaling
Circuit Associated Signaling is a technique that uses the same facility path for voice and signaling traffic. Historically this approach was selected to avoid the costs of separate channels for signaling and because the amount of traffic generated by signaling is small compared to voice, minimizing the chance for mutual interference. Circuit associated signaling can be contrasted with some common-channel signaling systems that use completely separate packet switched networks for signaling traffic.
Circuit Switching
Circuit switching is a process that establishes connections on demand and permits the exclusive use of those connections until released. Packet and message switching, primarily used in data communications networks are alternative switching techniques.
City Wide Digital Centrex
A city wide digital centrex is a capability to serve multiple business locations within a single NXX (exchange code), using multiple LEC central office Centrex switches. Outside callers are unaware that multiple business locations are involved.
CLEC
Competitive Local Exchange Carrier, most commonly referred to as Competitive Local Exchange Carrier.
CLLI
Common Language Location Identifier
CMIP
common management information protocol
Coaxial Cable
Coaxial Cable (also called coax cable or coax) consists of an insulated central conductor surrounded by a second cylindrical conductor that is clad with an insulating sheath. The outer conductor usually consists of copper tubing or copper braid.
COC
central office connections
Codec
Codec is a contraction of coder and decoder; a device that encodes analog signals into digital signals, for transmission through a network in digital format, and decodes received digital signals back into analog signals.
Common Channel Signaling (CCS)
CCS is a signaling system developed for use between stored program control digital switching systems, in which all of the signaling information for one or more trunk groups is transmitted over a dedicated signaling channel, usually, but not always completely separate from the user traffic bearing facilities.
Common Management Information Protocol (CMIP)
CMIP is the OSI protocol for network management. A structure for formatting messages and transmitting information between reporting devices (agents) and data collection programs, developed by the International Standards Organization and designated ISO/IEC 9596.
Communications
Communications is the process of representing, transferring, interpreting or processing information (data) among persons, places, or machines. Communications implies a sender, a receiver, and a transmission medium over which the information travels. The meaning assigned to the data must be recoverable without degradation.
Conditioning
Conditioning is an adjustment made to the electrical characteristics of a cable pair to improve its performance for a specific use.
Conductor
In electrical circuits, a conductor is any material that readily permits a flow of electrons (electrical current) through itself. Analogously, optical fibers are sometimes said to conduct light waves and are also referred to as conductors.
Corporation for Open Systems (COS)
COS is a nonprofit organization composed of manufacturing, service, and user organizations in the computer communications area. Seeks to facilitate the development of the international, multi-vendor marketplace through the development, introduction, and verification of OSI and ISDN standards and by ensuring vendor equipment interoperability.
CO
central office
CPU
central processing unit
Cross Connect
1.in a premises distribution system, equipment used to terminate and administer communications circuits. In a wire cross connect, jumper wires or patch cords are used to make circuit connections, between horizontal and backbone wiring segments. 2. in transmission systems a patch panel for connecting circuits.
CSDC
circuit-switched digital capability
CSMA/CD
Carrier sense multiple access with collision detection; a local area network contention based access control protocol technique by which all devices attached to the network "listen" for transmissions in progress before attempting to transmit themselves and, if two or more begin transmission simultaneously, are able to detect the "collision". In that case each backs off (defers) for a variable period of time (determined by a preset algorithm) before again attempting to transmit. (Defined by the IEEE 802.3 standard).
CSR
Centrex station rearrangement
CSU
channel service unit
Customer Premises Equipment
Customer Premises Equipment is all telecommunications terminal equipment located on the customer premises. except coin operated telephones.
Call - This is a connection between two or more users with the intent of exchanging information.
Call Back - This is a security method with which a user calls into a system and requests to be called back by the system at a particular, predetermined number.
Caller - Anyone who makes a call.
Caller ID - The service that allows someone being called to see the caller's name and phone number.
Call Progress - This is the status of the telephone line. It can be busy, ringing, not ringing, etc.
Call Waiting - This is a service that tells you if someone is trying to call you when you are already using the line (i.e., talking with someone else).
Capacitor - This is an electronic device for storing electric charge.
Capture Effect - This effect occurs when two signals are received that are the same (or nearly the same) frequency. The stronger signal will appear in the output.
C-Band - The portion of the electromagnetic spectrum allotted for satellite transmission; it is the 4 to 8 GHz frequency transmission range. Specifically, the 3.7 to 4.2 GHz band is used as the downlink, and the 5.925 to 6.425 GHz band serves as the uplink.
Card - This term refers to a computer peripheral that can be connected internally (i.e., directly), without any cables, to a computer, such as a modem.
Caret - This is the character "^".
Carrier - This term refers to: (1) a company, such as a local telephone company, that provides circuits dedicated to communication, and (2) an electrical signal capable of being modulated to carry information.
Carrier Detect (CD) - This is a light on most modems that signifies, when lit, that the modem is connected.
Carrier Frequency - The main frequency on which data, a voice, or video signal is sent. Common microwave and satellite communications transmitters operate in the band from one to fourteen GHz.
Carrier Signal - The basic radio, television, or telephony center of a frequency transmission signal.
Cassegrain Antenna - An antenna that places a subreflector at the focal point to reflect energy to or from a feed located at the apex of the main reflector.
CB - This stands for Citizen's Band and is low-power (up to 4 Watts), public radio that does not require FCC approval.
CD - See Carrier Detect.
CDMA - This stands for Code Division Multiple Access and refers to a multiple-access scheme where stations use wide-spectrum modulations and orthogonal codes to reduce the chance of interfering with each other.
Central Office (CO) - This is a place where lines are joined to switching equipment (which control connections).
Channel - A frequency band, 6 MHz wide in the US, in which a specific broadcast signal is transmitted. Channel frequencies are determined in the US by the Federal Communications Commission (FCC).
Character - This is a letter, numeral, or symbol.
Characters per Second (CPS) - This is the number of characters that can be sent over the phone lines in 1 second.
Chat - A mode that allows two or more people to communicate with each other in real time over a network using modems.
Checksum - This is the sum of a group of data items that is used for error checking. Received information packets must have the same number of bits present during the initial transmission.
Chip - This is the physical structure of an integrated circuit.
Circuit - This is an electrical device that provides a path for electrical current to flow, or more generally, it is a journey or route all the way around a particular place or area.
Circular Polarization - Some satellites transmit both right-hand rotating and left-hand rotating signals simultaneously on the same frequency. This technique effectively doubles the channel carrying capacity of the satellite.
City Code - Some foreign countries require you to dial a city code before the phone number you are trying to reach.
Clamp - A circuit that removes the energy dispersal signal component from the video waveform.
Clarke Orbit - This is the circular orbit in space 22,237 miles from the surface of the earth at which geosynchronous satellites are placed to revolve around the earth. It is named after Arthur C. Clarke, who first postulated its existence. Satellites in these orbits move at speeds that cause their angular velocity to match the angular rate of the rotation of the earth, causing them to appear stationary when viewed from a particular point on Earth.
Clear to Send (CTS) - This is when a receiving modem tells the calling modem.
C/N (Carrier to Noise Ratio) - This is the carrier-to-noise-ratio, which is the ratio of the received carrier power to the noise power in a given bandwidth; it is expressed in decibels (dB), which is a logarithmic scale.
CO - See central office.
Codec - A coder/decoder system for transmitting digital data.
Color Subcarrier - A particular subcarrier that is added to the main video signal; its purpose is to convey the color information.
Columns - A column contains an item of data within a row.
Command - This is a software instruction that causes a specific job to be done.
Command Buffer - This is a memory place where commands are store temporarily.
Command Set - A collection of commands. (See Command.)
Commercial Internet (.com) - This is the part of the internet that is provided by commercial services, allowing business usage of the internet.
Common Carrier - Any organization which operates communications circuits used by other people. Common carriers include the telephone companies as well as communications satellite owners, AT&T and others.
Communication Channel - This is a type of circuit, and it is a two-way information pathway.
Communications Protocol - These are procedures used to ensure a standardized transmission occurs.
Compatible - When one object can be used interchangeably with another.
Composite Baseband - The unclamped and unfiltered output of the satellite receiver's demodulator circuit. It contains all of the video information as well as all transmitted subcarriers, such as the color subcarrier.
Compression - This occurs when information is reduced in size but all of the necessary information is retained.
Compression Ratio - This is the ratio of the original size of data that is sent to the compressed size.
Computer Network - See Network.
Configuration - This is the software or hardware arrangements that define a computer (or telecom system) and determine what actions will be carried out (and how).
Connected - This means you are online.
Connect Speed - Modem speed in bps.
Connection - A electrical pathway between telephones or similar devices.
Control Channel - With a cellular telephone system there are a few channels that allow the base stations to transmit information to the cell phones in its area.
Conus - This stands for Contiguous United States.
Copyright - This protects an author's work from being directly copied by another.
Country Code - This is the standardized code that designates a certain country.
Coverage Area - A geographical area that is defined by the coverage of a particular satellite.
CPS - See characters per second.
Crash - This is the complete failure of software or hardware operation. The only available option is to restart from an initial condition.
CRC - See Cyclic Redundancy Check.
Cross Modulation - A form of distortion in which modulation from one or more carriers' signals is imposed on another carrier's signal.
CRT - This stands for Cathode Ray Tub, and is a glass device used in video displays (e.g. televisions).
C/T - Carrier-to-noise-temperature ratio.
CTRL - This is the abbreviation for the ConTRoL key-command.
CTS - See Clear to Send.
Cursor - This is the particular marker that points out the next place the text will next appear on your screen.
Cyclic Redundancy Check (CRC) - This is a common process that is used to validate the integrity of a block of data.
補(bǔ)充：
Client - A program or computer that is used to contact and obtain data from another program or computer, referred to as the server.
CLEC - Competitive Local Exchange Carrier. Deregulated local telephone companies resulting from the Telecommunications Act of 1996 that are competing for local exchange service, as well as for long distance and Internet service.
CO - Central Office. A telephone company’s building where subscribers’ lines are joined to the switching equipment to connect calls.
Cookie - A small data file sent to a Web browser by a Web server that is used to record a user's activities on a Web site. For instance, when you buy items from a site and place them in a "shopping cart," that information is stored in a cookie. When the browser requests additional files, the cookie information is sent back to the server. Cookies can remember other types of information, such as your password, so you don't have to re-enter it every time you visit a site. They also retain your preferences, so when return to a site, you can enjoy customized information. Cookies cannot read any other information stored in your computer.
Connectivity - The technical communications link between a computer system and the Internet.
Cramming – An illegal practice in which customers are billed for additional telephone features they didn't’t order.
CSSR – Customer Sales and Service Representative. These TDS Telecom employees work in the sales and service offices of our local operating companies. They answer customer questions, market services, and handle payments.
CST – Customer Service Technician. These TDS Telecom employees work in our local operating companies and provide installation and repair service for our customers.
CAB
Carrier Access Business
Cable
A cable is a group of metallic conductors or optical fibers that are bound together, usually with a protective sheath, a strength member, and insulation between individual conductors/fibers and for the entire group.
CABS
Carrier Access Billing System - We fully explain what a Carrier Access Billing System is on this website. See the main page of this website for more information.
CALC
customer access line charges
CAP
competitive access provider
Carrier
A carrier is a local (intra-LATA) or long distance (inter-LATA) telecommunications service providing organization. A waveform, pulsed or continuous, that is modulated by another information bearing waveform.
Carrier System
A carrier system is a transmission system for transmitting one or more channels of information by processing and converting to a form suitable for the transmission medium used. Carrier systems are classified as either analog carrier systems or digital carrier systems.
CBR
continuous bit rate
CCIS
common-channel interoffice signaling
CCITT
CCITT is the International Consultative Committee for Telephone and Telegraph, a consultative committee to the International Telecommunications Union (ITU) which recommend international standards for telephone and telegraph services and facilities to aid international connectivity and interoperability.
CCSA
common-control switching arrangement
CCS
centi-call seconds or common-channel signaling
CDMA
code division multiple access
Cell Relay
Call relay is the process of transferring data in the form of fixed length packets called cells. Cell relay is used in high-bandwidth, low-delay, packet-like switching and multiplexing techniques. The objective is to develop a single multiplexing/switching mechanism for dividing up usable capacity (bandwidth) in a l-manner that supports its allocation to both isochronous (e.g., voice and video traffic) as well as packet data communications services. Standards groups have debated the optimum cell size. Small cells favor low delay for isochronous applications but involve a higher header to user information overhead penalty than would be needed for most data applications. The current CCITT specification for BISDN is for a 53-byte cell which includes a 5- byte header and a 48-byte payload.
Centi Call Seconds (CCS)
CCS is a unit of the average traffic intensity of a facility during a period of time, a CCS is 100 call seconds of traffic during one hour. Therefore a single traffic source, e.g., one call that generates traffic 100% of the time produces 36 CCS of traffic per hour, i.e., 3600 seconds of traffic every 3600 seconds. An equivalent amount of traffic could also be generated by 10 sources that only generate traffic 10% of the time. That is, 10 sources of traffic generating 3.6 CCS each, contributes the same total traffic as a single 36 CCS traffic source. An alternative measure for traffic is erlangs where 1 erlang equals 36 CCS.
CENTRal EXchange (Centrex)
Centrex is a LEC-provided switching service for business customers that permits station-to-station dialing, listed directory number service, direct inward dialing and station number identification on outgoing calls. The switching functions are usually performed in a central office. Digital Centrex offers the advanced features of fourth generation PBXs, without the need to purchase or lease equipment and, in most cases, eliminates the need for floor space, electrical prime power and heating, ventilation and air conditioning.
Central Offices (CO)
A central office is a telephone company building in which network equipment such as switches are installed.
Channel
A channel is a single communications path in a transmission medium connecting two or more points in a network, each path being separated by some means; e.g., spatial or multiplex separation, such as frequency or time division multiplexing. "Channel" and "circuit" are often used interchangeably, however circuit can also describe a physical configuration of equipment that provides a network transmission capability for multiple channels. The characteristics of channels and circuits are determined by the network equipment and media used to support them.
Channel Service Unit (CSU)
Channel Service Units (CSUs) and Data Service Units (DSUs) are required to connect digital customer premises equipment (CPE) to carrier networks. A CSU is network channel terminating equipment (NCTE) attaching as CPE to telephone company's digital circuits, and protecting the network from harm. Other CSU functions include line conditioning and equalization, error control (e.g., bipolar signal violations), and the logical ability to respond to local and network loop back circuit testing commands. See Data Service Units (DSU).
Circuit Associated Signaling
Circuit Associated Signaling is a technique that uses the same facility path for voice and signaling traffic. Historically this approach was selected to avoid the costs of separate channels for signaling and because the amount of traffic generated by signaling is small compared to voice, minimizing the chance for mutual interference. Circuit associated signaling can be contrasted with some common-channel signaling systems that use completely separate packet switched networks for signaling traffic.
Circuit Switching
Circuit switching is a process that establishes connections on demand and permits the exclusive use of those connections until released. Packet and message switching, primarily used in data communications networks are alternative switching techniques.
City Wide Digital Centrex
A city wide digital centrex is a capability to serve multiple business locations within a single NXX (exchange code), using multiple LEC central office Centrex switches. Outside callers are unaware that multiple business locations are involved.
CLEC
Competitive Local Exchange Carrier, most commonly referred to as Competitive Local Exchange Carrier.
CLLI
Common Language Location Identifier
CMIP
common management information protocol
Coaxial Cable
Coaxial Cable (also called coax cable or coax) consists of an insulated central conductor surrounded by a second cylindrical conductor that is clad with an insulating sheath. The outer conductor usually consists of copper tubing or copper braid.
COC
central office connections
Codec
Codec is a contraction of coder and decoder; a device that encodes analog signals into digital signals, for transmission through a network in digital format, and decodes received digital signals back into analog signals.
Common Channel Signaling (CCS)
CCS is a signaling system developed for use between stored program control digital switching systems, in which all of the signaling information for one or more trunk groups is transmitted over a dedicated signaling channel, usually, but not always completely separate from the user traffic bearing facilities.
Common Management Information Protocol (CMIP)
CMIP is the OSI protocol for network management. A structure for formatting messages and transmitting information between reporting devices (agents) and data collection programs, developed by the International Standards Organization and designated ISO/IEC 9596.
Communications
Communications is the process of representing, transferring, interpreting or processing information (data) among persons, places, or machines. Communications implies a sender, a receiver, and a transmission medium over which the information travels. The meaning assigned to the data must be recoverable without degradation.
Conditioning
Conditioning is an adjustment made to the electrical characteristics of a cable pair to improve its performance for a specific use.
Conductor
In electrical circuits, a conductor is any material that readily permits a flow of electrons (electrical current) through itself. Analogously, optical fibers are sometimes said to conduct light waves and are also referred to as conductors.
Corporation for Open Systems (COS)
COS is a nonprofit organization composed of manufacturing, service, and user organizations in the computer communications area. Seeks to facilitate the development of the international, multi-vendor marketplace through the development, introduction, and verification of OSI and ISDN standards and by ensuring vendor equipment interoperability.
CO
central office
CPU
central processing unit
Cross Connect
1.in a premises distribution system, equipment used to terminate and administer communications circuits. In a wire cross connect, jumper wires or patch cords are used to make circuit connections, between horizontal and backbone wiring segments. 2. in transmission systems a patch panel for connecting circuits.
CSDC
circuit-switched digital capability
CSMA/CD
Carrier sense multiple access with collision detection; a local area network contention based access control protocol technique by which all devices attached to the network "listen" for transmissions in progress before attempting to transmit themselves and, if two or more begin transmission simultaneously, are able to detect the "collision". In that case each backs off (defers) for a variable period of time (determined by a preset algorithm) before again attempting to transmit. (Defined by the IEEE 802.3 standard).
CSR
Centrex station rearrangement
CSU
channel service unit
Customer Premises Equipment
Customer Premises Equipment is all telecommunications terminal equipment located on the customer premises. except coin operated telephones.