Cabling Administration is a process in telecommunication system engineering for premise wiring that includes all aspects of premise wiring related to documenting and managing, testing the system as well as the architectural plans for the system.
CAC: Connection (or Call) Admission Control
Connection Admission Control (CAC), also known as Call Admission Control, refers to the set of actions taken by the network during the call set-up phase (or during call re-negotiation phase) in order to determine whether a connection request can be accepted or should be rejected. In the voice over IP communications, the CACs prevent an IP network from becoming clogged with traffic to the point of being unusable. When a network's capacity is consumed, admissions control mechanisms prevent new traffic from being added to the network. When calls traverse the WAN, admissions control assumes paramount importance. Within the LAN in which bandwidth is not a problem, CAC is less critical. CAC could also be a set of actions taken by each ATM switch during connection setup to determine whether a connection's requested QoS will violate the QoS guarantees for established connections. CAC also is used when routing a connection request through an ATM network.
CALEA: Communications Assistance for Law Enforcement Act
Communications Assistance for Law Enforcement Act (CALEA) is a US law established in 1994 that defines obligations of telecommunications carriers to assist law enforcement in executing electronic surveillance (or wiretapping) pursuant to court order or other lawful authorization. The purpose of CALEA is to preserve the ability of law enforcement to conduct electronic surveillance in the face of rapid advances in telecommunications technology.
A call, also knowns as phone call in telecommunication, is the attemted connection to establish a voice conversation between two people.
Call Accounting System is the software that is essential to telecom cost management typically for business or organizations. It usually provides services like phone call tracking, telephone usage monitoring, corporate bill back, telephone usage bulling to, and etc.
Call Center is a functional area within an organization, business or an outsourced, separate facility that exists solely to answer inbound or place outbound telephone calls; usually a sophisticated voice operations center that provides a full range of high-volume, inbound or outbound call-handling services, including customer support, operator services, directory assistance, multilingual customer support, credit services, card services, inbound and outbound telemarketing, interactive voice response and web-based.
Call Collision is the contention that occurs when a terminal and data circuit-terminating equipment (DCE) specify the same channel at the same time to transfer a call request and handle an incoming call. When call collision occurs, the DCE proceeds with the call request and cancels the incoming call. Call collision also refers to the condition that occurs when a trunk or channel is seized at both ends simultaneously, thereby blocking a call.
Call Deflection is a feature of voice over IP (VoIP) that automatically redirects a call from the called endpoint to another endpoint (usually a voice mailbox) when the called endpoint is busy. Call deflection is one of several forms of call diversion (also known as call forwarding) defined under the H.450.3 specification.
Call Duration is 1. the time between (a) the instant a connection, i.e., off-hook condition at each end, is established between the call originator and the call receiver and (b) the instant the call originator or the call receiver terminates the call. 2. In data transmission, the duration of the information transfer phase of an information transfer transaction.
Call Filter is a feature in an ISDN moden that is performed by the port monitor to determine if the caller has authorization to run the type of service requested. The caller ID (telephone number of the calling system) must be listed in the Call Filter file, together with a list of service types which that caller is authorized to use.
Call Management refers to the following functions in telecommunication system: 1. In telegraphy, it's about route selection, signaling, and circuit usage and availability for a call. 2. In universal personal telecommunications, it is about the ability of a user to inform the network how to handle incoming calls in accord with certain parameters, such as the call originator, the time of day, and the nature of the call.
Call Originator is an entity, such as a person, equipment, or program that originates a call.
Call Priority is the priority assigned to each origination port in circuit-switched systems. This priority defines the order in which calls are reconnected. Call priority also defines which calls can or cannot be placed during a bandwidth reservation.
Call Process Signals refer to signals for call processing. Examples of Call Process Signals are various audible tones (such as dial tone, ringing tone, audible ringing tone, audible busy tone, and congestion tones) or announcements that inform the subscriber of the call progress status.
Call Set-up is one of the many states of call processing. The call Set-up state establishes a communications path: (1) between the calling party and the called party, and (2) between the calling party and the network entities.
In telecommunication world, Call Setup Time is the time required to establish a switched call between users. For data communication, Call Setup Time refers to the the overall length of time required to establish a circuit-switched call between terminals, i.e., the time from the initiation of a call request to the beginning of the call message.
Call Waiting Tone is a special service that allows a busy line to answer an incoming call by flashing the switch-hook. Audible ring (instead of line busy) is applied to the calling line, and the Call Waiting Tone is applied to the called line. (So that only the called party hears the tone, the connection is momentarily broken, and the other party to that connection experiences a moment of silence.) Flashing the switch-hook places the existing connection on hold and connects the customer to the waiting call. Call Waiting Tone is two bursts of 440 Hz at -13 dBm0/frequency for 0.3 seconds plus or minus ten percent every ten seconds.
Called Party refers to a end user (person or his device) that receives a telephone call initiated by a calling part.
Caller ID is, also known as calling number delivery (CND), a telephone service intended for residential and small business customers. It allows the called Customer Premises Equipment (CPE) to receive a calling party's directory number and the date and time of the call during the first 4 second silent interval in the ringing cycle.
Calling Card refers to a physical object, often in the form of a wallet-sized card made of plastic or paper, which contains contractual information as to using postpaid or prepaid long distance services from the calling card provider. Calling card based long distance phone call is a form of dial-around, which is a two-step method for selecting a long distance service provider on a call-by-call basis.
Calling Card Service Prompt Tone
Calling Card Service Prompt Tone is used to inform the customer that his/her credit card information must be keyed in. The first 60 milliseconds of this composite tone is 941 Hz and 1477 Hz which is the DTMF '#'. This tone will release and DTMF to dial pulse converter in the connection. Calling Card Service Prompt Tone is 941 Hz and 1477 Hz at -10 dBm0/frequency at -3 Transmission Level Point for 60 milliseconds and then 440 Hz and 350 Hz at -7 dBm0 for 0.940 seconds exponentially decayed from -10 dBm per frequency at -3 Transmission Level Point at time constant of 0.2 seconds.
Calling Party is a user (person or his device) that initiates a telephone call over the public siwiched telephone network. It is also refered as Call Originator.
CAM: Carrierless Amplitude Modulation
Carrierless Amplitude Modulation (CAM) refers to the original approach for modulation of a Digital Subscriber Line (DSL) signal. Currently, Discrete multitone (DMT) is the preferred modulation alternative over CAP
CAMA: Centralized Automatic Message Accounting
Centralized Automatic Message Accounting (CAMA) refers to an automatic message accounting system that serves more than one switch from a central location. When using CAMA, human intervention may be required.
Camp-On, also referred as Called-party Camp-on, is a telecommunication system feature that enables the system to complete an access attempt in spite of issuance of a user blocking signal. The system constantly monitors the busy user until the user blocking signal ends, and then proceed to complete the requested access.
CAP: Carrierless Amplitude Phase Modulation
Carrierless Amplitude Phase (CAP) modulation is a viable alternative for the Digital Subscriber Loop (DSL) systems such as the HDSL, ADSL and VDSL. The conventional two-dimensional CAP-16 line code is extended to a three-dimensional scheme. The three-dimensional system is designed so that the new overall transfer matrix maintains perfect reconstruction of the transmitted information. The system is designed by solving a minimax optimization problem by using the sequential
CAP: Competitive Access Provider
Competitive Access Provider (CAP) is a type telecommunication service providers that provide local telecommunications services mainly to business customers in competition with a local Bell Operating Company (BOC). Teleport and MFS are the two major CAPs operating in major metropolitan areas in the United States.
Capping refers to the activity of ISPs (Internet Service Provider) to limit (capping) the accessing speed of cable modem so that cable modem ISPs can easily distribute bandwidth among users. The upload cap in particular is intended to discourage users to run big servers. In general, these caps are also put in place to make the system more robust. At slower speeds, packet loss is usually lower and the system can handle worse signal quality.
Carrier refers to the following definitions: 1. in telecommunication service, it refers a company which provides physical media circuit for telecommunication service. 2. in telecommunication technology, it refers to an physical signal (optical, electrical, infrared and etc.) at a continuous frequency capable of being modulated to variation of physical format in order to carry information. 3. in networking, some physical media for transmitting signal like wideband circuits. T1 line for instance, is also called carrier which means that telecommunication signal is being carried and transmitted by them.
Carrier Frequency refers to the nominal frequency of a carrier wave, the frequency of the unmodulated electrical wave at the output of an amplitude modulated, the center frequency of a frequency modulation signal, frequency modulated, or phase modulated transmitter of the output of a transmitter when the modulation is zero.
Carrier Hotel refers to a type of data center where multiple telecommunications network or service providers, such as tacos or internet service providers, site their connections to one another's networks (points of presence).
Carrier service provider is a company offering telecommunication (voice or data) service between points in a state or in one or more countries. Examples of Carrier service provider are AT&T, British Telecom etc.
Carrier system refers to, in the telecommunication system, a system utilizing a method of providing several communications channels over a single path by modulating the data, voice or video transmissions onto a higher frequency carrier wave for transmission between nodes of a network. Loosely, in the transmission context of telecommunication system, it is sometimes a synonym with carrier.
Carrier wave is the wave form that transports the signal wave, and is a sinusoidal component of a complex wave form of much higher frequency than the modulating signal which contains the information.
Carson bandwidth rule refers to a rule that defines the approximate bandwidth requirements of communications system components for a carrier signal. The signal is frequency modulated by a continuous or broad spectrum of frequencies rather than a single frequency.
CAS: Channel Associated Signaling
Channel Associated Signaling (CAS), one of two types of telecom signaling technologies, is the transmission of signaling information within the information band, or in-band signaling. This means that voice signals travel on the same circuits as line status, address, and alerting signals. As there are twenty-four DS0 channels on a full T1 line, CAS interleaves signaling packets within voice packets. Various types of CAS signaling are available in the T1 world. The most common forms of CAS signaling are loopstart, groundstart, and E&M signaling. The biggest disadvantage of CAS signaling is that the network uses bits from information IP packets, such as voice packets, to perform signaling functions. CAS signaling is often referred to as robbed-bit signaling. The other type of signaling is the common channel signaling (CCS), which is an out of band signaling technology. SS7/C7 and ISDN are based on the CCS.
Casual Calling is a feature that allows a customer to place a long distance call using an ANI (Automatic Number Identification) (including undefined ANIs) to access a given carrier, other than the default long distance provider. Customers can place casual calls by dialing a special access code (a "CIC" code) before the area code and telephone number. For example, if the originator is calling from a non-coin phone, they may dial 1010555+destination number and have the call routed through WorldCom and billed to the originating phone number.
Casual Customer refers to any person or organization (not necessary to pre-subscribe to the carrier.) that dials any CIC (Carrier Identification Code) code to place a long distance call.
Cause Codes indicate the reason for ISDN-call failure or completion. Typically, cause codes are ranged from 0 to 127. Cause code values of 128 and higher aren't sent over the network.
Clear Channel (CC) refers to the following definitions in the telecommunications system: 1. Channel in which the full bandwidth (e.g., 64 kbps) is used for transmission; no portion of the channel is set aside for control, framing or signaling. 2. a channel through which non-encrypted traffic can flow. Clear channels place no security restrictions on transmitted data. 3.a line that connects two points which is wholly dedicated to traffic between those two points. This is in contrast with a shared line, such as a frame relay, in which a user must share the frame network with other subscribers.
Country Code (CC), part of a telephony numbering plan, indicates the country for which the telephone number is serviced. For example, the country code of the US is 001 and for P. R. China, is it 086.
CCBS: Completion of Call to Busy Subscriber
Completion of Call to Busy Subscriber (CCBS) is a feature in telephony system. It works like this when a called party is busy, this supplementary service enables the calling party to be connected to a called party after they have completed their call.
CCH: Connections per Circuit Hour
Connections per Circuit Hour (CCH) refers to the following meanings: 1. A unit of traffic measurement expressed as the number of connections established per hour at a switching point. 2. A unit of traffic measurement represents the rate at which circuits are established at a switch.
CCITT: Consultative Committee for International Telegraph and Telephone
Consultative Committee for International Telegraph and Telephone (CCITT) was an international organization responsible for the development of communications standards. CCITT now became the International Telecommunications Union Telecommunication Standardization Sector (ITU-T).
CCITT: International Telegraph and Telephone Consultative Committee
CCITT is the abreviation of the International Telegraph and Telephone Consultative Committee in France. CCITT is standards body based in Geneva that publishes "recommendations" on standards used throughout the world communication industry.
Centi-Call Seconds is a unit used (in North America) to quantify the aggregate of traffic running in a network, which is one hundred call seconds or one hundred seconds of telephone conversation. That means 1 CCS could be 2 calls of 50 seconds duration or 20 calls of 5 seconds duration.
Common Channel Signaling (CCS) is a signaling method used in telephone networks that separates signaling information from user data. In CCS, one channel of a communications link is exclusively used for the sole purpose of carrying signaling for establishment and teardown of calls. The remaining channels are used entirely for the transmission of voice or data. In most cases, a single 64kbit/s channel is sufficient to handle the call setup and teardown traffic for numerous voice and data channels. The most common CCS signalling methods in use today are ISDN and SS7.
CCSS7: Common Channel Signaling System 7
Common Channel Signaling System 7, abreviated CCSS7 or CCS7, CCIS7, or C7, is the signaling method used in countries other than the North America where the signaling system is called Signaling System #7 (SS7). Both CCSS7 and SS7 are based on the same common channel signaling technology and are interoperable across the network.
CCT: Continuity Check Transceiver
Continuity Check Transceiver (CCT) is a device in the switch system that verifies outgoing trunk continuity for a common-channel signaling call and reports the results as well.
Call Detail Block (CDB) consists of several Call Data Elements. The CDB is generated at a Certain Point in Call (PIC). For example, a CDB is generated when the call is answered, released, and so on.
Call Detail Element (CDE) is a data element that includes a basic information field within a billing record of telephone calls. Examples of a CDE are the calling number, the called number, and so on.
Call Detail Record (CDR), a term used in both PSTN and VOIP systems, is the telephone call record written to a database for use in post-processing activities. A typical CDR includes the origination and destination addresses of the call, the time the call started and ended, the duration of the call, the time of day the call was made and any toll charges that were added through the network or charges for operator services, among other details of the call. CDRs are primiarily used for billing and network analysis.
Call Detail Reporting (CDR) is a feature in both PSTN and VOIP systems that provides a database of information about each call, including date, time, duration, called number, calling number, call direction, service type, and associated inverse multiplexing session and port. Because the network carrier bills for bandwidth on an as-used basis, and bills each connection in an inverse multiplexed call independently, CDR is used to understand and manage bandwidth usage and the cost of each inverse multiplexed session.
Caller-entered Digits (CED) are the digits entered by a caller on a touch-tone phone in response to prompts. Either a peripheral (ACD, PBX, or VRU) or the carrier network can prompt for CEDs.
CELP: Code Excited Linear Prediction
Code Excited Linear Prediction (CELP), also known as Code-Book Excited Linear Predictive, is a loss compression algorithm used for low bit rate (e.g.,4800 bps in U.S. Fed-Std-1016) speech coding. CELP coding, at 4800 bps, breaks the performance barrier of most Government standards, providing Consortium ratings of "very good" intelligibility and "excellent" quality, comparable to 32,000 bps (CVSD). CELP is used in ITU-T Recommendations G.728, G.729, G.723.1.
Center Frequency refers to the middle frequency of the bandwidth of a channel.
Central Member is the center component of a fiber cable. It serves as an anti-buckling element to resist temperature-induced stresses. Sometimes serving as a strength element, the central member is composed of steel, fiberglass, or glass-reinforced plastic.
Centralized Intercept Bureau Order Tone
Centralized Intercept Bureau Order Tone is a 0.5 second burst of 1850 Hz at -17 dBm0/frequency that tells the centralized intercept bureau operator that a call has reached the position.
Centrex is central office exchange service, a type of PBX service in which switching occurs at a local telephone station instead of at the company premises. Typically, the telephone company owns and manages all the communications equipment necessary to implement the PBX and then sells various services to the company. With Centrex, there is no onsite switching at the customer premise and all customer connections go back to the Centrial Office of the service provider.
CEPT: Conference of European Posts and Telecommunications
Conference of European Posts and Telecommunications (CEPT), also known as Committee of European Posts & Telephones, is a collaborative organization for telecommunications regulators in 43 European countries. The organization deals with questions regarding harmonization and radio/telecommunications. For example, CEPT defines the 2.048Mbps European E1 signal made up of 32 voice-frequency DS0 channels.
Call Forwarding (CF) is a phone service feature that allows the customer to forward their phone to another phone number (for example, you can forward your home phone number to your cell number if you know you are going to be away from home).
Call Forwarding Busy (CFB) is a service that enables your incoming calls that encounter a busy condition or are not answered, after a customer-designated interval, to be automatically forwarded to another local or long distance phone number where network facilities permit.
Call Forward No Reply (CFNR) is a service feature that forwards all calls to another extension number or an outside number automatically if it is not answered after 6 rings:
CFU: Call Forward Unconditional
Call Forward Unconditional (CFU) is a service feature that always forwards all calls (or only outside calls) to another extension number (or an outside number).
Change-back is the inverse function of change-over. It is the procedure for transferring signaling information (traffic) from one or more alternate signaling links to a signaling link that has become available.
Change-over is the procedure for transferring signaling information from a signaling link (which is experiencing failure or is required to be cleared of traffic) to one or more alternate (different) signaling links.
Channel refers to a one-way telecommunications link or transmission medium through which information or signal is transmitted from a sender (or transmitter) to a receiver. They may be either physical or logical depending on the application. A Radio Frequency (RF) channel is a physical channel, whereas control and traffic channels within the RF channel would be considered logical channels.
Channel Associated Signaling is a form of digital communication signaling. As with most telecommunication signaling methods, it uses routing information to direct the payload of voice or data to its destination. With CAS signaling, this routing information is encoded and transmitted along the same link as the payload itself. This results in lower available bandwidth for the payload, normally reducing a 64 Kbit/s DS0 to 54 kbit/s.
Channel Noise Level refers to the following definitions depending the context: 1. the ratio of the channel noise at any point in a transmission system to an arbitrary level chosen as a reference. 2. the noise power density spectrum in the frequency range of interest. 3. the average noise power in the frequency range of interest
Channelized, in a telecommunications environment, means that the line that communications have been transmitted over contains more than one message thread, separated in some fashion. Typical channelization methods include packetizing, frequency differentiation, time division multiplexing (TDM). For example, Channelized T1 sub-divides the 1.44 Mbps bandwidth into 24 channels of 64 Kbps each.
Channelized E1 refers to that an E1 access link of at 2.048 Mbps is subdivided into 30 B-channels and 1 D-channel of 64 Kbps each. Channelized T1 and channelized E1 can be configured for ISDN PRI, synchronous serial, and asynchronous serial communications.
Channelized T1, also known as fractional T1, refers to that an access link operating at 1.544 Mbps is subdivided into 24 channels (23 B-channels and 1D-channel) of 64 Kbps each. The individual channels or groups of channels connect to different destinations. Channelized T1 and channelized E1 can be configured for ISDN PRI, synchronous serial, and asynchronous serial communications.
Check Bit refers to the following definitions: 1. A bit, such as a parity bit, derived from and appended to a bit string for later use in error detection and possibly error correction. 2. A data bit associated with a character or block for the purpose of checking the absence of error within the character or block.
Check Digit is a form of redundancy check used for error detection in telecommunication system. It's the decimal equivalent of a binary checksum. It consists of a single digit computed from the other digits in the message.
Churn refers to the situation that many subscriber additions and then un-subscription. If the churn ratio is high for a service provider, it is not good, because that the cost is typically high to get a customer to sign in a service and the service provider has a problem to keep customers.
CIC: Carrier Identification Code
Carrier Identification Code (CIC) refers to the following definitions: 1. a numeric code assigned by the North American Numbering Plan (NANP) Administrator for the provisioning of selected switched services. The numeric code is unique to each entity and is used by the telephone company to route the call to the trunk group designated by the entity to which the code was assigned. 2. a 4-digit code that controls the routing applied to a call by the originating switch.
CIC: Circuit Identification Code
Circuit Identification Code (CIC) is information identifying a circuit between a pair of exchanges, for which signaling is being performed (14 bits in the ISDN user part)
CIR: Committed Information Rate
Committed Information Rate (CIR), one of parameters in a Service Level Agreement (SLA), is the data transfer rate for an individual virtual circuit (VC) in an ATM or Frame Relay network, for which the provider commits to deliver. The provider may send any data in excess of this rate for this VC if its network has capacity at the time. This choice typically affects the price of each VC.
A circuit is a communications path between two or more points among a network. A physical circuit is actually a wire or a part of a wire which connects two computer or network devices for permanently dedicated communications. A virtual circuit may be a temporarily established logic connection between two network devices for communications within certain time limit.
Circuit Noise Level is the ratio of the circuit noise at any point in a transmission media of telecommunications system to a nominal reference point; this ratio is either expressed in decibels (above the reference noise, dbrn) or in adjusted decibels (dba, which reflects a specified adjustment due to external interference).
Circuit Switching is a technology in which a dedicated physical circuit path must exist between sender and receiver for the duration of the "call." Used heavily in the telephone company network, circuit switching can be contrasted with contention and token passing as a channel-access method, and with message switching and packet switching as a switching technique.
Circuit Transfer Mode is an telecommunications term that refers to an ISDN transfer mode through permanent bandwidth allocation.
Circuit-level Inverse Multiplexing
Circuit-level Inverse Multiplexing is a method of inverse multiplexing in which the inverse multiplexer slices the data stream into equal portions, and transmits each portion over an available circuit. The receiving end adjusts for network-induced delay and reassembles the data packets into their proper order. The AIM and BONDING protocols define how circuit-level inverse multiplexing works. Applications that require transparent digital circuits, such as videoconferencing, nailed-up backup and overflow, and bulk file transfer applications, use circuit-level multiplexing.
A circulator is a passive device with three or more ports in which the ports can be accessed in such an order that when a signal is fed into any port it is transferred to the next port, the first port being counted as following the last in order. There are circulators both for electronic signals and for light, the latter being used in optical fiber networks.
City Wide Digital Centrex is a capability to serve multiple business locations within a single NXX (exchange code as in xxx-xxx-xxxx telephone number), using multiple LEC central office Centrex switches. Outside callers are unaware that multiple business locations are involved.
Cladding is the material, usually glass, that surrounds the core of the optical fiber. Light bounces off the interface between the cladding and fiber and returns to the fiber.
Class 4 Switch, also called tandem switch, is used for long distance communications in the PSTN. A class switch 4 is an intermediate switch or connection between an originating telephone call or location and the final destination of the call.
Class 5 Switches provide telecommunication services using TDM (Time Division Multiplex) technology from basic dial-tone to advanced voice services and data network access to subscribers within a defined locality or local loop. Class 5 switches are deployed at a central office (CO) by service providers for both local and long distance telephony services, vs. the Class 4 switches are only for long distance and trunking services.
Class of Service Tone is the Class of Service signal that is used at a toll board operating as an 'A" board to identify the class or service of the calling customer. The indication may be high, low, or no tone. Class of Service is a single burst of either High Tone or Low Tone for 0.05 to 1 seconds.
CLASS: Custom Local Area Signaling Service
Custom Local Area Signaling Service (CLASS) is one of an identified group of network-provided enhanced services. A CLASS group for a given network usually includes several enhanced service offerings, such as incoming-call identification, call trace, call blocking, automatic return of the most recent incoming call, call redial, and selective forwarding and programming to permit distinctive ringing for incoming calls.
Clean Power refers to electrical power which has been conditioned and/or regulated to remove electrical noise from the output power.
Clear-back Message is a signal (message) sent in the backward direction to indicate that the called party is no longer "off-hook".
Clear-forward Message is a signal sent in the forward direction to terminate a call (or a call attempt) so that the associated circuits can be released. This signal is normally originated when the calling party hangs-up the phone.
CLEC: Competitive Local Exchange Carrier
Competitive Local Exchange Carrier (CLEC) is a company which provides local telephone service - other than the incumbent Local Exchange Carrier (LEC). Much like a LEC, a CLEC provides telephone service within a LATA. To handle InterLATA long distance calls, the CLEC will connect to an IXC. Most CLEC's will use the local loop (UNE-L) belonging to the incumbent Local Exchange Carrier. The telecommunication act of 1996 forced the incumbent LEC's to lease access to their local loop (UNE-L) to CLEC's at wholesale prices. Between 1996 and 2004, the FCC also required LEX's to lease other network elements (UNE-P) to the CLEX's.
CLID: Calling Line Identification
Calling Line Identification (CLID), also known as Caller ID, refers to the following definitions in the telecommunications system: 1. A service available on digital phone networks that tells the person being called which number is calling them. The central office equipment identifies the phone number of the caller, enabling information about the caller to be sent along with the call itself. Synonymous with ANI (Automatic Number Identification). 2. A facility provided by a switched network which can notify a called terminal of the telephone number of the line from which a call originated.
SS7 Cross Link (C-link) connects STPs performing identical functions into a mated pair. A C-link is used only when an STP has no other route available to a destination signaling point due to link failure(s). Note that SCPs may also be deployed in pairs to improve reliability; unlike STPs, however, mated SCPs are not interconnected by signaling links.
Clipping is a distortion of voice signals in which the beginnings of final sounds are cut off.
CLLI Code: Common Language Location Identification Code
Common Language Location Identification (CLLI) Code is an eleven character alphanumeric descriptor used to identify switches, points of interconnection, and other categories of telephone network elements and their locations. All CLLI Codes are stored in a national database maintained by Telcordia.
Communications Module (CM) is a component of 5ESS switch by Lucent/AT&T which is the interface between the Administrative Module (AM) and Switching Modules (SMs). The main function of a CM is to provide a message interface between the AM and the SMs to control digital space switching. It has four main functional elements: 1. Message Switch (MS). 2. Communications Module Control Unit (CMCU). 3. Time Multiplex Switch (TMS). 4. Network, Control and Timing (NCT) links.
CMCU: Communications Module Control Unit
Communications Module Control Unit (CMCU) refers to one of the functional elements of the Communications Module of 5ESS switch (see "CM"). It contains the network clock, and the metallic interface to the Time Multiplex Switch (TMS) and the Network, Control and Timing (NCT) links. The CMCU controls the operation of the message switch by interfacing the MMPs and the TMS.
C-message, also called C-curve or C-message wight, refers to the shape of the curve that represents the sensitivities to different tones to humans ear.
Coded Mark Inversion (CMI) refers to an encoding algorithm specified for STS-3c transmissions and DS-1 systems which doubles the data rate. A zero [0] is sent as a low to high [1] transition, while a one is sent as wither a one [1] or zero [0] depending on the previous state. If the previous state was high the one is sent as zero [0], it sent as one [1] otherwise.
Call Management System (CMS) is a reporting package used on ACDs and PBXs made by Avaya. Avaya CMS is an optional database, administration and reporting application designed for enterprises that receive a large volume of telephone calls and have complex contact center operations. Avaya CMS provides an administrative interface to the automatic call distribution (ACD) feature of the DEFINITY Server, enabling your contact center managers to generate reports, administer ACD parameters and monitor call activities to help determine the most efficient service possible for your customers.
CNM: Customer Network Management
Customer Network Management (CNM) refers to a feature of ATM network which allows customers of ATM public networks to monitor and manage their portion of the carrier's circuits by providing the function and ability in the user interface to monitor physical ports, virtual paths, usage parameters, and quality of service parameters.
Central Office (CO) is the local switching facility of a telephone company to which telephones are connected. Central Office is a common carrier switching center in which trunks and loops are terminated and switched. Synonyms exchange, local central office, local exchange, local office, switching center, telephone exchange.
Coin Collect Tone is an audible tone of telephone system over a coin recording-completing trunk informs the originating toll operator that the local operator or coin control circuit has collected the charge. Coin Collect Tone is a steady Low Tone.
Coin Denomination tones is audible tone of telephone system which enables the operator to determine the amount deposited in coin telephones. Coin Denomination Tones for the old 3 slot payphones were: Nickel - One tap of 1050 Hz and 1100 Hz (bell) Dime - Two taps of 1050 Hz and 1100 Hz (bell) Quarter - One tap at 800 Hz (gong).
Coin Phone is the public phone accepting coins from caller as payment.
Coin Return Tone is audible tone of telephone system over a coin recording-completing trunk informs the originating toll operator that the local operator or coin control circuit has returned the change when the connection is not completed (also called coin-refund tone). Coin Return Tone is a single 5 to 1 second burst of High Tone.
Common Carrier is a licensed, private utility company that supplies local or long distance communication services to the public at regulated prices. The term differs from private carrier, which operates solely for the benefit of one entity and does not offer services to the general public.
Communication Security refers to measures and controls used in telecommunication systems for security purposes. It may include crypto security, transmission security, emission security, traffic-flow security and physical security of equipments.
Communication Source refers to sources that encode message data and transmit the information via a telecommunication channel to one or more receivers.
Communications Subsystem, a general term in telecommunications systems, describes a functional entity or operational assembly that is smaller than the larger assembly under consideration.
Communications System refers to a set of all the individual telecommunications networks components including switches, transmission systems, relay stations, etc. to perform a telecommunications task.
Communications Deception refers to a scheme in telecommunications system that can deliberately transmit, retransmit or alternate information of communications to mislead an adversary's interpretation of the communications.
Communications Line refers to the physical link (such as wire or a telephone circuit) that connects one or more devices to one or more other devices.
Communications Protection refers to the application of communications security measures to telecommunications systems in order to: 1. deny unauthorized users access to sensitive unclassified information of value; 2. prevent disruptions of telecommunications services; 3. ensure the authenticity of information handled by telecommunications system.
Companding, also known as compansion, comes from the combination of compressing and expanding, which is a method of reducing the effects of a channel with limited dynamic range. The use of companding allows signals with a large dynamic range to be transmitted over facilities that have a smaller dynamic range capability. Companding reduces the noise and crosstalk levels at the receiver.
Compandor is the combination of a compressor and expandor used in telecommunication channels to improve transmission performance. It reduces the dynamic range of the transmitted signal at the transmitter (compressor) and recover this signal to the original dynamic range at the receiver (expander).
Completed Signaling is one of several signaling methods. In Completed Signaling, after one signal message (or element) has been sent, a second signal message cannot be sent in the same direction until the first signal message has been acknowledged (by a response in the opposite direction).
Compressor conducts the process or function of amplifying small signals while extremely large signals are compressed (at the transmitter).
Concentrator, a type of multiplexor, combines multiple channels onto a single transmission channel. A concentrator usually provides communication capability between many low-speed, usually asynchronous channels and one or more high-speed, usually synchronous channels. Usually different speeds, codes, and protocols can be accommodated on the low-speed side.
Conducted Interference refers to interference resulting from noise or unwanted signals entering a device by conductive coupling in the circuit.
Conference Operation refers to an operation in the telecommunications system that a telephone call can be established in such a way that three or more stations can communicate directly with all the other stations. A three way call is one of the example.
Confirmation Tone is one of the audible tones generated in the telephone system that is used to acknowledge receipt by automatic equipment of information necessary for special services. It is currently used for:
• Speed Calling - dialed number has been recorded.
• Call Forwarding - dialed number has been recorded and service is activated.
• Call Forwarding - service is deactivated.
Confirmation Tone is 350 Hz and 440 Hz at -13 dBm0/frequency on for 0.1 second, off for 0.1 second and then on for 0.3 seconds.
Contract Tariffs refers to services and rates based on contracts negotiated with individual customers, but theoretically available to all customers. Former AT&T has filed several hundred contract tariffs.
Control refers to one of the three entities in the ATM reference model. The control plane addresses all signaling and control related issues such as session setup and tear-down, and for network parameter changes during a session. The other two entities are user plane for the actual data transmission and the management plane for network management issues. The concept and model of user plane, control plane and management plane has been extended to other telecommunication technology groups beyond the ATM technology.
Control Signal refers to a signal in telecommunication used for auxiliary functions with equipment connections to the Point of Termination (POT) or to the demarcation point. Examples are the toll connection restriction and the party identification functions.
Controlled Re-routing is a scheme in signaling. Using a controlled methodology, the signaling information (traffic) is transferred from an alternate signaling route to the normal signaling route, when it becomes available.
CONUS: CONtiguous United States
CONtiguous United States (CONUS) refers to the 48 contiguous U.S. states. It is used primarily to designate the operating range or authorization of a satellite or radio facility.
Convolutional code is a type of forward error correction code using a shift register containing a number of stages to shift the input bits one at a time to produce a coded output. With the convolutional code, (a) each m-bit information symbol (each m-bit string) to be encoded is transformed into an n-bit symbol, where m/n is the code rate (n >= m) and (b) the transformation is a function of the last k information symbols, where k is the constraint length of the code.
Central Office Terminal (COT) refers to one of the UDLCs (Universal Digital Loop Carrier) terminals (the other one is called remote terminal). Both remote terminal and central office terminal interface with analog signals, convert it to digital signals, and transport them to the other side where the reverse is performed.
Country Code refers to the two or three digit codes used for International calls outside of the North American Numbering Plan area codes. Dial: 011 + country code + city code + local phone number) (e.g. in "011 + 86 + 10 + 1234- 5678", 86 = China, 10 = Beijing).
Calling Party Category(CPC), defined in the SS7 ISUP by ITU-T, characterizes the station used to originate a call and carries other important state that can describe the originating party. Based on the CPC parameter from the calling network, the called network can do some special processes related to the calling party category, just like overriding the Do Not Disturb (DND) list and some other barring services.
CPE: Customer Premises Equipment
Customer Premises Equipment (CPE) is a type of terminating equipment, such as terminals, telephones, and modems, supplied by the telephone company, installed at customer sites, and connected to the telephone company network. CPEs may also refer to any telephone equipment residing on the customer site regardless who supplied them.
Call ProGress (CPG) refers to the status of the telephone line. It can be busy, ringing, not ringing, etc
CPNIE: Called Party Number Information Element
Called Party Number Information Element (CPNIE) is a type of Information Elements in the ISDN messages defined in ITU-T Q.931.
CPSIE: Called Party Subaddress Information Element
Called Party Subaddress Information Element is a type of Information Element in the ISDN messages defined in ITU-T Q.931.
Cramming refers to the unauthorized addition of services or features to your telephone service by service providers. These services may be such things as voice mail, caller ID, special service packages or fee-for-service charges such as 900 calls.
Cross Connect is a method of connecting the various elements in a cabling system.
Cross-Connection refers to a connection scheme between terminal blocks on the two sides of a distribution frame, or between terminals on a terminal block.
Cross-office Check refers to the activity in call processing procedure which is a check on the circuits between two or more exchanges to verify an acceptable transmission path exists.
Customer Routing Point (CRP) is an AT&T's terminology for third-party processors that accept routing requests from the CCSS7 network.
Call Reference Value (CRV) is the number carried in all Q.931 (I.451) messages that provides an identifier for each ISDN call. Call Reference Value is a scheme to distinguish call-legs signaled between two entities.
Controlled Slip (CS) is an Error Event in DS1/T1 interface, which is the replication or deletion of the payload bits of a DS1 frame. A Controlled Slip may be performed when there is a difference between the timing of a synchronous receiving terminal and the received signal. A Controlled Slip does not cause an Out of Frame defect.
Carrier Serving Area (CSA) is a geographic customer area that is consolidated into a single digital transmission by the telephone company. Each carrier serving area (CSA) is served by a digital loop carrier (DLC), which multiplexes hundreds of analog lines into one high-speed digital trunk. The physical size of a CSA is based on the number of lines the DLC supports and the population density
CS-ACELP: Conjugate Structure Algebraic Code Excited Linear Prediction
Conjugate Structure Algebraic Code Excited Linear Prediction (CS-ACELP) is the CELP voice compression algorithm providing 8 kbps, or 8:1 compression, standardized in ITU-T Recommendation G.729.
Component Sub-layer (CSL) is the upper layer of TCAP (Transaction Capabilities Application Part). The CSL defines the actual messages, or components, that are contained in the TSL (Transaction Sub-layer Messages).
CSU/DSU: Channel Service Unit/Data Service Unit
Channel Service Unit (CSU)/Data Service Unit (DSU), two units often combined into one, is a digital interface device that connects end-user equipment to the local digital telephone loop. The Channel Service Unit (CSU) is a device that connects a terminal to a digital line. The DSU component is a device used in digital transmission that adapts the physical interface on a data terminal equipment (DTE) device to a transmission facility, such as T1 or E1.
Channel Service Unit (CSU) is a device that connects a terminal to a digital line. This is a digital interface device installed on end-user premises that directly connects end-user equipment (terminal) to the local digital telephone loop. Typically, Channel Service Unit (CSU) and the data service unit (DSU) devices are packaged as a single unit called CSU/DSU.
Call Transfer (CT) is a service feature of telecommunications which allows customers to transfer a call to any other number.
CTI: Computer Telephony Integration
Computer Telephony Integration (CTI) is the technology that links the computer, telephone and other services such as voice messaging and fax. CTI improves the handling of the customer relationship. For example, customer details can be on screen while an agent answers the call.
Clear To Send (CTS) is a signalling message transmitted from the data communications equipment (DCE) indicating to the data terminal equipment (DTE) that it may begin data transmission. For example, a networking equipment such as IEEE 802.11 wireless station may send a CTS in response to an RTS (Request to Send) message. The CTS message silences all wireless stations in its vicinity to avoid collision and enables the sender of the RTS message to begin data transfer.
Customer-Originated Trace is one of group features made possible by Local Area Signaling Service. It lets the terminating party request an automatic trace of the last call received. The trace includes the calling line directory number and time and data of the call. This information is transmitted to a designated agency, such as the telephone company or law enforcement agency.
Cutover is the physical switch of telephone lines from one telephone system to another, or a replacement of old telephone equipment like switches by a totally new switches, or the installation of a new system. It's usually performed over the weekend and midnight.
Cut-Through Dialing refers to a call that the number dialed is "10"+CIC+" #" followed by an Authorization Code for IntraLATA calls.
Call Waiting (CW) is a feature that allows a user to be notified of another incoming call while a call is already in progress, and gives the user the ability to answer the second call while make the first call remains on hold.