Even experts need occasional help with telecom terms. We have combined glossaries from several sources to simplify finding the definitions you need.
Search Tip: To locate a specific acronym, word or phrase on a particular page, type CTRL+F (on a PC) or Command+F (on a Macintosh).
The entrance area in a central office for all types of outside plant cables that carry subscriber lines and interoffice transmission facilities.
Displays the caller's name and telephone number on a display device, so you'll know who is calling before you answer.
Displays the caller's telephone number on a display device, so you'll know who is calling before you answer.
Call Forwarding allows you select the telephone number where you would like all your calls to be forwarded — cell, home, or another number in your office.
Callers will automatically be transferred to a pre-selected telephone number so someone else can answer the call for you.
Callers are automatically transferred when your line is busy or when you are not available to answer. Calls are forwarded to a phone number you designate, whether home, another office location or answering service.
Callers will be automatically transferred to a pre-selected telephone number when you can't answer the telephone so someone else can take the call.
Callers will automatically be transferred to a pre-selected telephone number* so someone else can answer the call for you.
The number transmitted through the network that identifies the calling party. Technically, a Common Channel Inter-office Signaling (CCIS) parameter that refers to the number transmitted on an out-of-band basis through the SS7 signaling network identifying the calling party's telephone number. Also known as Automatic Number Identification (ANI).
The geographic name that identifies the region of calling plan usage.
With Call Waiting, you'll be alerted of a new incoming call if you're already on the line.
Alerts you of a new incoming call if you're already on the line, showing you the name and/or number of the person trying to reach you. Since you'll know the identity of your second caller, you can choose whether to answer the new call or continue with your current conversation.
A network that provides interconnection in a confined geographic area such as a campus or industrial park. Such networks operate over fairly short distances, and do not require public rights-of-way.
See Competitive Access Provider.
A package of directory listings for an end user with multiple listings under the same name.
A unique three- or four-digit access identification code that is assigned by Telcordia Technologies for use with certain switched access services. The CIC identifies the caller's long distance carrier.
An Industry Forum that is chaired rotationally by CLECs and ILECs; its charge is to provide guidelines for carrier-to-carrier performance metrics in the state of New York.
Usage dialed using a calling card or by dialing the prefix, 1010XXX.
See Constant Bit Rate.
See Common Channel Signaling Network.
See Common Channel Signaling System 7.
See Copper Distributed Data Interface.
Network transmission format that uses small data packets of the same size, called cells. The cells are fixed length, and can be transmitted at very high rates.
A carrier service that supports the receipt and transmission of ATM cells between end users in compliance with ATM standards and implementation specifications.
ATM performance parameter that specifies the average transit delay of cells between a source and destination over a given virtual circuit.
A high-capacity land-based mobile (also known as wireless) telephone system wherein channels assigned to the system are divided among several geographical cells covering a defined service area. A cellular system is capable of reusing the same channels in different cells within the service area. Use of many small cells with low transmitter powers permits intensive reuse of channels in a given area, thereby increasing system capacity.
A process using centrally located equipment, associated with a tandem or a toll switching office, for automatically recording billing data for end-user customer dialed calls originating from several local central offices.
Verizon building where end users' lines are joined to switching equipment that connects other end users to each other, both locally and via long distance carriers. The central office contains the associated inside plant network elements required to perform this function, such as distribution frames, interoffice facility termination points, and so on. Also known as End Office and Entity.
The three digit switch entity indicator which is defined by the D, E, and F digits of a 10-digit telephone number. Each NXX code contains 10,000 station numbers. Historically, entire NXX code blocks have been assigned to specific individual local exchange end office switches.
The primary point at which outside plant facilities terminate within a wire center for interconnection to other telecommunications facilities within the wire center. Also known as Main Distribution Frame (MDF).
The first three digits (NXX) of a seven-digit telephone number under which up to 10,000 telephone numbers are grouped; exchange area boundaries are associated with the central office code. Several central office codes may be served by a single central office switching system.
Often referred to as the switch, the telephone company facility that connects subscribers to each other, locally and long distance. CO switches include the following:
NOTE: Central office switches may be employed as combination end office switch/tandem office switches (combination Class 5/Class 4).
A class of central office service that provides the equivalent of PBX service from a telephone company switching system. Permits station-to-station dialing, direct inward dialing to a particular station, and station identification on outgoing calls. Centrex® provides a direct line for each employee and a customizable package of business communications features without the financial and hardware demands of a stand-alone office telephone system. Learn more.
An electrical or photonic (for fiber optic based systems) communication path between two or more points of termination.
Equipment that performs one or more of the following functions: termination of a digital facility; regeneration of digital signals; detection and/or correction of signal format error; and remote loopback.
See Committed Information Rate.
A two-way communication path.
The specific Interexchange Carrier trunk group that is required to carry the call for SS7 messages.
A connection over a virtual circuit-based network that provides service to end users that is indistinguishable from a real, point-to-point, fixed-bandwidth circuit.
Switching system in which a dedicated physical circuit path exists between sender and receiver for the duration of the call. Used heavily in service provider company networks, circuit switching is often contrasted with contention and token passing as a channel-access method, and with message switching and packet switching as a switching technique.
See Competitive Local Exchange Carrier.
See Common Language Location Identifier.
11-character code that identifies the wire center from which a call originated.
The end of a switched access service that receives ringing and dial tone, and transmits address signals.
The frequency-weighted, short-term average noise within an idle channel. Frequency weighting, called C-message, is used to account for the variations in 500-type telephone set transducer efficiency and end user annoyance to tones as a function of frequency.
A noise measurement factor.
See Commercial Mobile Radio Service.
The C-message frequency-weighted noise on a channel with a holding tone that is removed at the measuring end through a notch (very narrow band) filter.
See Central Office.
See Central Office.
A transmission line in which one conductor is a wire at the center of the cable; the other conductor surrounds the center wire with a layer of insulating material between them. Coaxial cable can transmit greater bandwidth than twisted pair (TP) wires.
A non-distributed backbone in which all network segments are interconnected via an internetworking device. A collapsed backbone may be a virtual network segment that exists in a device such as a hub, a router, or a switch.
An arrangement whereby the facilities of one party (the Collocating Party) are terminated with the equipment necessary to provide interconnection or access to the network elements offered by the second Party. This equipment is installed and maintained at the premises of the second Party (the Housing Party). All such services and facilities used for Colocated Interconnection are for carriage of non-switched interstate traffic. For purposes of Colocation, the premises of a Housing Party are described as a Housing Party Wire Center, other mutually agreed-upon locations of the Housing Party, or any other location for which Colocation has been ordered by the FCC or the state Commission. Verizon provides Colocation housing under terms, rates, and conditions as described in tariffs filed with the FCC and Commissions.
Colocation may be physical or virtual. For physical colocation, the Collocating Party installs and maintains its own equipment in the Housing Party's premises. For virtual colocation, the Housing Party owns, installs, and maintains equipment that is purchased by the Collocating Party, located in the Housing Party's premises, and dedicated to use by the Collocating Party. Learn more.
A radio communication service between mobile stations or receivers and land stations, or by mobile stations communicating among themselves, that is provided for profit, and that makes interconnected service available to the public.
Any applicable state regulatory body having jurisdiction over telecommunications carriers.
The specified transport speed that a frame relay network will maintain between service locations.
A telecommunications company that provides communication transmission services, such as telephone and telegraph, to the public. The local telephone service provider is an example of a common carrier.
A transmitting method for network facilities that carry the actual voice or data traffic of the call.
High-speed specialized packet-switched communications that is separate (out-of-band) from the public packet-switched and message networks; protocol used on the CCS/SS7 network.
Connection of one party's signaling point of interconnection to the other party's signal transfer point for the exchange of SS7 messages.
A high-speed specialized packet-switched communications network that is separate (out-of-band) from the public packet-switched and message networks. Carries addressed signaling messages for individual trunk circuits and/or database-related services. The network was developed by the Consultative Committee for International Telephone and Telegraph (CCITT) and the American National Standards Institute (ANSI).
CCS/SS7 carries addressed signaling messages for individual trunk circuits and/or database-related services between signaling points in the CCS network using the SS7 signaling protocol.
11-character code that identifies the wire center from which a call originated.
A line, trunk, pay telephone line, or other facility provided under the local general service tariffs of the ILEC, terminated on a central office switch. A common line-residence is a line or trunk provided under the residence regulations of the local general services tariffs. A common line-business is a line provided under the business regulations of the local general services tariffs.
Common carriers that provide local service. These companies compete with local telephone service providers to provide access services that connect end-users to long distance companies.
Any company or person authorized to provide local exchange services in competition with an ILEC. A CLEC provides similar or identical telecommunications services to the ILEC.
A mechanism for allocating very large amounts of bandwidth for transport of a payload associated with a 'superrate service', which is a service at a transmission rate greater than the normal maximum rate of OC-1. The set of bits in the payload is treated as a single entity, as opposed to being treated as separate bits or bytes or time slots. The payload, therefore, is accepted, multiplexed, switched, transported and delivered as a single, contiguous chunk of payload data.
The adjustment of the electrical characteristics of transmission lines to improve their performance for specific uses. Conditioning involves the tuning of the line or addition/deletion of equipment to improve its transmission characteristics.
Excessive network traffic.
Network management effort to control traffic flow so that switches and end-stations are not overwhelmed with information because of excessive network traffic.
Delay-intensive applications such as video and voice, that must be digitized and represented by a continuous bit stream. CBR traffic requires guaranteed levels of service and throughput.
The inter-machine signaling system that has been traditionally used in North America for the purpose of transmitting the called number's address digits (telephone number) from the originating end office to the switching machine that will terminate the call. In this system, all dialed digits are received by the originating switching machine, a path is selected, and the sequence of supervisory signals and outpulsed digits is initiated. No overlap outpulsing, ten-digit Automatic Number Identification (ANI), information digits, or acknowledgment wink are included in this signaling sequence.
A version of FDDI that runs on copper twisted-pair wires, rather than on fiber.
See Customer Premise Equipment.
A connection provided to a Collocator at the digital system cross connect, main distribution frame or other frame or panel between the CLEC’s equipment and equipment or facilities owned by Verizon.
See Channel Service Unit.
See Cell Transfer Delay.
Verizon's CustoFLEX 2100 system is a central office-based, full featured, voice communications service. Central office-based means all equipment required to operate the system is in the Verizon central office. Learn more.
A generic term describing several local service offerings such as incoming-call identification, call trace, call blocking, automatic return of the most recent incoming call, automatic re-dial, selective call forwarding, etc.
Telephone terminating equipment, such as handsets, PBXs, and modems located on the customer's premises and connected to the phone service provider network.
CustoPAK® is an advanced, flexible telephone system ideal for small businesses with a minimum of two employees. It turns existing single or multi-line telephones into an efficient business communications system with direct lines and customizable features for each employee.
Physical changing of lines from one system to another, usually at the time of a new system installation.
Back to Top