Telecommunications Glossary

Everything you ever wanted to know about telecommunications terms. We are constantlly updating this page and adding new terms. If you have any comments or contributions, please email us at glossary@LDSearch.com . Enjoy reading!

Abbreviated Dialing

A feature that permits the calling party to dial the destination telephone number in fewer than normal digits. Abbreviated Dialing numbers must be set up in advance of their use. Speed Dialing is a typical example of Abbreviated Dialing.

Account Codes

Also known as Project Codes or Bill-Back Codes. Account Codes are additional digits dialed by the calling party that provide information about the call. Typically used by hourly professionals (accountants, lawyers, etc.) to track and bill clients, projects, etc.

Agent

A person or organization that acts on behalf of another. In the telecommunications industry, Agents typically are independent individuals or companies that market the services of a carrier as if they were employees of that carrier.

Aggregator

An independent entity that brings several subscribers together to form a group that can obtain long-distance service at a reduced rate. Subscribers are billed by the original IXC. The aggregator only provides the initial set-up of the plan. He usually provides no service after that. Different than a reseller.

Alternate Access

A form of local access where the provider is not the LEC, but is authorized or permitted to provide such service.

Alternate Access Carriers

Local exchange carriers in direct competition with the RBOCs. Normally found only in the larger metropolitan areas. Examples are Teleport and Metropolitan Fiber Systems.

Alternative Operator Services

Operator services provided by a company other than a LECRBOC or AT&T that is authorized to provide such service.

ANI - See Automatic Number Identification.

 

Answer Supervision

The off-hook indication sent back to the originating end when the called station answers.

ARI

Automatic Room Identification (Hotel/Motel room number)

Automatic Number Identification

Originating Number
(1) The number associated with the telephone station(s) from which switched calls are originated (or terminated).
(2) A software feature associated with Feature Group D (and optional on Feature Group B) circuits. ANI provides the originating local telephone number of the calling party. This information is transmitted as part of the digit stream in the signalling protocol, and included in the Call Detail Record for billing purposes.
(3) ANI may also be used to refer to any phone number.

Baby Bells - See RBOC Backbone

 

Ballot

A release form that authorizes a customer's long-distance phone service to be switched to (another) long-distance carrier, or reseller. Also know as a Letter Of Agency or LOA.

BAN - Billing Account Number

Used by telephone companies to designate a billing account, i.e., a customer or customer location that receives a bill. A customer may have any number of BANs.

Banded Rates

Tariffed rates which may be changed by the carrier within a specified range. Frequently, state commissions require notice to the commission prior to each change. Banded rates are being used less frequently today.

Bell Customer Code

A three-digit numeric code, appended to the end of the Main Billing Telephone Number, that is used by Local Exchange Carriers to provide unique identification of customers.

Bell Operating Company - BOC

The local (or regional) telephone company that owns and operates lines to customer locations and Class 5 Central Office Switches. BOCs have connections to other COs, Tandem (Class 4 Toll) offices and may connect directly to IECs like WorldCom, AT&T, MCI, Sprint, etc. BOC may refer to the nineteen Bell Operating Companies that are owned by the seven RHCs (Regional Holding Companies) (not including Cincinnati Bell or Southern New England Telephone). The BOC role was originally defined by the 1982 Modified Final Judgement that specified the terms of the AT&T Divestiture). For Example, the three BOCs: Mountain Bell, Northwestern Bell and Pacific Northwest Bell are owned by the U.S. West RHC. Each BOC may service more than one LATA, but BOCs are generally constrained from providing long distance service between LATAs.

Billing Account Number - BAN

Used by telephone companies to designate a customer or customer location that will be billed. A single customer may have multiple billing accounts.

Bill-To-Room

A billing option associated with Operator Assisted calls that allows the calling party to bill a call to their hotel room. With this option, the carrier is required to notify the hotel, upon completion of the call, of the time and charges.

Block Calls

Prevent calls from completing to the requested destination. May be due to network problems (outage, overload, etc.), or by customer request (e.g. block calls from-or-to certain NPAs, NXXs, States, LATAs, etc.).

BOC - See Bell Operating Company

 

Bong

An interactive signal that prompts the originating end user to enter additional information. For example: 1010555 Bong (Enter Destination) Bong (Enter Billing information)

BTN - Billing Telephone Number

The phone number associated, for billing purposes, with the Working Phone Number.

Bypass

Access an IEC other than the customer's Equal Access carrier by dialing 10+CIC Code. (e.g. Bypass to WorldCom by dialing "1010555"). See Walkthrough, CIC Code

Calling Card

A telecommunication credit card with an AuthCode for using a long distance carrier when the customer is away from their home or office (ANI).

Carrier

A telecommunications provider which owns switch equipment.

Carrier Identification Code - CIC

A three digit number used with Feature Groups B and D to access a particular IEC's switched services from a local exchange line. One or more CIC codes are assigned to each carrier. (i.e. there may be multiple CICs per ACNA). See Bypass

Casual Calling

Allow any ANI (including undefined ANIs) to access a given carrier. 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

Any person or organization that dials any CIC Code. (Not necessary to presubscribe to the carrier.)

Centrex

A service that is functionally similar to a customer-premise PBX, but provided by means of equipment located in a Central Office.

CIC

See Carrier Identification Code (WorldCom = "555")

Class of Service - COS

A special limitation on what numbers can and cannot be called. International, 809, 809 + Canada, 48 contiguous states, etc.

COCOT

Customer Owned Coin Operated Telephone

Coin Phone

A coin-operated pay phone with restricted access to some services (e.g. International calling). Coin phones have subclasses of Public, Semi Public, and Private.

Collect

A call that is paid for by the receiving/destination phone number. Requires approval/authorization of the person being called.

Common Carrier

A carrier that holds itself out as serving the public (or a segment thereof) indifferently (i.e., without regard to the identity of the customer and without undue discrimination). Common carriers may vary rates based on special considerations and may in fact serve only a small fraction of the general public.

Contract

A legally-binding agreement between a vendor and a customer to provide Products, Services or Features in a specified quantity and quality, for a specified price, during a specified period of time.

Contract Tariffs

Services and rates based on contracts negotiated with individual customers, but theoretically available to all customers. AT&T has filed several hundred contract tariffs.

CONUS-CONtiguous United States

The 48 contiguous U.S. states. Used primarily to designate the operating range or authorization of a satellite or radio facility.

Country Code

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. "011 + 91 + 22 + 123- 4567" 91 = India, 22 = Bombay)

Cutover

The exact date/time that a phone number, circuit, etc. is scheduled to be (or was) moved from one implementation (carrier, etc.) to another. (e.g. moving an 800 number from MCI to WorldCom).

Cut-Through Dialing

"10"+CIC+" #" followed by an AuthCode for IntraLATA calls.

DA - Directory Assistance

Phone Number Lookup Service

DAL - Dedicated Access Line

A non-switched circuit from the customer to a carrier.

DDD - Direct Distance Dialing

Any switched telecommunication service (like 1+, 0++, etc.) that allows a call originator to place long distance calls directly to telephones outside the local service area without an operator.

Deactivation

A request to terminate service (or the process of terminating service)

Dedicated Line

A private line leased from a telecommunications carrier.

Default Carrier

Your regular Dial-1 carrier. Call 1-700-555-4141 to find your default carrier.

Dial

To Place A Call On A Switched Network. The term "dial" is obsolete - based on rotary dial phones and electromechanical relay switches (which are nearly non-existent in modern telephone systems.) Touch Tone service recognizes dual tones that are generated as each telephone key is pressed. Where Touch Tone service is not available, telephones and switches electronically "pulse" signals that emulate the older rotary dial telephones. The terms "place" a call or "originate" a call are more accurate than "dial".

Dial Tone

Ready To Place/Originate A Call. When the off hook indication is received at a central office, a dial tone signal is sent to the originating caller on a switched network to indicate that the switch is ready to accept a number.

Dialer

Equipment that pulses out a standard dial protocol signal.

Digital

A device or method that uses discrete variations in voltage, frequency, amplitude, location, etc. to encode, process, or carry binary (zero or one) signals for sound, video, computer data or other information. For example, a digital clock displays the time as discrete numeric values, rather than angular displacement of analog hands. Digital communications technology generally permits higher speeds of transmission with a lower error rate than can be achieved with analog technology. When analog signals are received and amplified at each repeater station, any noise is also amplified. A digital signal, however, is detected and regenerated (not amplified). Unlike amplification, any noise (less than a valid signal) is eliminated by digital regeneration.

Directory Assistance - DA

An information service whereby operators assist customers in obtaining the telephone number(s) they wish to call.

Equal Access

(AT&T Divestiture - 1982 Modified Final Judgement) The provision of one-plus capability to interLATA competitors of AT&T. Customers should be able to reach the carrier of their choice by dialing 1+ the long-distance number. The MFJ and the FCC require local exchange carriers to provide equal access (most central offices now have this capability). Equal Access may also refer to a more generic concept under which the BOCs must provide access services to AT&T's competitors that are equivalent to those provided to AT&T.

Facilities-Based Carrier - FBC

A carrier that uses its own facilities to provide service, in contrast with resellers, that purchase the services of other carriers and then retail the services to customers. (Most facilities-based carriers use the services of other carriers to some extent.)

FCC - Federal Communications Commission

Regulates interstate communications: licenses, rates, tariffs, standards, limitations, etc. Appointed by U.S. President .

IC

Interexchange Carrier - IXC - IEC (IEC is preferred). A company providing long-distance phone service between LECs and LATAs.

IEC - Interexchange Carrier

IC - IXC (IEC is preferred). A company providing long-distance phone service between LECs and LATAs.

IEC Miles - Interexchange Carrier (Long Distance) Miles

 

IXC Miles

On a Price Quote, the coordinates of Location A and Location B are used to calculate mileage-dependent line charges.

Interexchange

Communication between two different LATAs.

InterLATA

Communication between Local Access Transport Areas. 1982 MFJ requires LECs to use an IEC for InterLATA services.

International

Between multiple nations.

Interstate

Between multiple states. Interstate communications are regulated by the FCC.

IntraLATA

Communication within a Local Access Transport Area. 1982 MFJ allows LEC to handle these calls without an IEC.

Intrastate

Communication within a single state. Intrastate communications are regulated by each state's PUC.

IXC

1) Interexchange Carrier (IEC is preferred). A company providing long-distance phone service between LECs and LATAs.
2) Interexchange Circuit. A circuit that connects PoPs.

IXC MilesInterexchange Carrier (Long Distance) Miles

On a Price Quote, the coordinates of Location A and Location B are used to calculate mileage-dependent line charges.

LATA

Local Access Transport Areas (200 in the U.S.). A geographic service area defined in the AT&T Modified Final Judgement. The RBOCs (baby Bells) and GTE are restricted to operations within, but not between, LATAs. Long distance service within a LATA is provided by the LEC. Service between LATAs is provided by an IEC. LATAs are represented by a 3-character code, and there are 164 of them across the country.

LEC - See Local Exchange Carrier

 

LEC BAN - Billing Account Number

3-digit number appended to the billing phone number used as the LEC customer number. Groups all ANIs for a customer.

LEC Billing

Arrangement whereby the Local Exchange Carrier invoices the customer for some or all telecommunications services.

LEC Card

The billing arrangement which enables the caller to bill calls to an authorized calling card issued by a local exchange carrier.

LEC Charges

Charges that are the responsibility of the local exchange carrier.

Letter Of Agency - LOA

A document that authorizes changing the service provider. (See RespOrg, 800 Portability)

Local Access

Local Loop. The connection from a subscriber to the Central Office. The portion of a circuit connecting the LEC's CO with the customer's premise equipment across the local network.

Local Access Provider

Any organization that is authorized to provide local access. (May or may not be the LEC.)

Local Exchange Carrier - LEC

The local or regional telephone company that owns and operates lines to customer locations and Class 5 Central Office Switches. LECs have connections to other COs, Tandem (Class 4 Toll) offices and may connect directly to IECs like WorldCom, AT&T, MCI, Sprint, etc.

Local Exchange Service

Local phone calls.

Long Distance Carrier

A company providing long-distance phone service between LECs and LATAs.

Message Toll Service - MTS

Pay-by-the-minute switched long distance services. Includes conventional long distance and measured WATS.

NPA Area Codes, NXX Exchanges and XXXX Line Numbers

The process for assigning 10-digit (3+3+4) North American telephone numbers

NASC - 800 Number Administration and Service Center

The organization that administers the SMS/800 system for the reservation, registration and administration of all North American 800 numbers for all carriers. (See 800 Portability, RespOrg and SMS/800)

NPA - Numbering Plan Areas

North American "Area Codes." (3 digits: 2-to-9, 0-or-1, 0-to-9. Middle digit to expand soon)

NPA-NXX Routing

Area Code / Exchange Routing. Route calls based on the originating ANI NPA-NXX.

NPA Routing

Area Code Routing. Route calls based on the originating ANI NPA (area code.)

NPA Split

Subdividing an area code, with the creation of a new area code. This is necessary when the number of telephones in an area code (NPA) grows to an excessive number.

NUS

NASC SMS/800 Number Search. SMS application used to find available 800 numbers and reserve them for up to 60 days.

NXX

Exchanges (First 3 digits of a 7-digit phone number). (2-to-9, 0-to-9, 0-to-9) (Digits 4, 5 and 6 in a 10 digit NANP telephone number - NPA-NXX-XXXX).

OCC - Other Common Carrier

Not part of the original AT&T system.

Off Hook

The signal that the telephone receiver has been lifted (activated). Originating off hook activates a dial tone on switched networks. Destination off hook completes a call (and activates minute-by-minute billing for long distance calls).

One Plus - 1+

Customer ability to access the long distance service provider of their choice by first dialing 1, then the long distance number. Equal Access guaranteed by the 1982 AT&T MFJ. 1+ is an outbound service where the calling station pays the charges.

Operator Service Call - OSC

A call that is placed through a human or automated operator (0+).

Operator Service Provider - OSP - OS Provider

The vendor that supplies operator service.

Outbound

Outward Sending - Call Originating - Dialing Out

Payphone

A public (or private) telephone that accepts coins or encoded credit cards.

Person-to-Person

Operator assisted phone call - only billed if the specified person is available.

PIC - Primary Interexchange Carrier

The IEC that 1+ calls are routed to. Specified by ANI.

PIC Charges

A LEC charge for changing the PIC. Often paid by the new IEC. If a LEC sends a PIC charge to a customer, the new IEC will typically credit the customer's account.

PIC Freeze

A PIC Freeze prevents the long distance from being switched for the specified ANIs. Useful to prevent slamming, or the unauthorized switching of long distance services.

PIC Request

A request record sent to a LEC asking for an ANI to be activated, deactivated or changed in some way.

PIC Response

A response record sent by a LEC (corresponding to a previous PIC Request) with a response code that indicates whether the request was performed. (Some LECs return non-standard PIC Response codes.)

PICC - Aka: National Access Fee, Presubscribed Interexchange Carrier Charge, Presubscribed Line Charge, Regulatory Related Charge, or Carrier Line Charge. Pronounced "pixie." This charge started on January 1, 1998 as part of the FCC overhaul of telephone fees. Long distance companies pay a flat fee to the local telephone company when you pre-subscribe your telephone line to their long distance service. (Sometimes referred to "Dial 1" or "Plus 1" service) The charge is designed to compensate the local telephone companies for the costs associated with providing "local loop" service. If a consumer or business has not selected a long distance company for its telephone lines, the local telephone company may bill for the PICC. Although every long distance company is charged the same flat rate per line, long distance companies are allowed to recharge you for this in any way they see fit, and each company uses a different method to charge this carrier specific fee. It is normally not presented to you in such a way that you would think it is a competitive pricing issue. But it is! Some companies do not charge this fee at all, and some charge a carrier specific flat fee. This is NOT a tax. Please note that on July 1, 2000 the FCC ruled that long distance companies no longer will have to pay this fee to local companies for residential lines, or single line businesses. The charge continues for multiple line businesses. Many long distance companies are still charging you for this, even though they aren't paying it anymore!

Point Of Presence - POP

The physical access location interface between a local exchange carrier and an Interexchange Carrier fiber network. The point to which the telephone company terminates a subscriber's circuit for long distance service or leased line communications.

Point-To-Point

Non-switched, dedicated communication circuit.

POP - (See Point Of Presence)

 

POTS - Plain Old Telephone Service

 

Primary Interexchange Carrier

The long distance company that is automatically accessed when a customer dials 1+.

Private Line

Uses dedicated circuits to connect customer's equipment at both ends of the line. Does not provide any switching capability (unless supported by customer premise equipment). Usually includes two local loops and an IEC circuit.

Provisioning

The process by which a requested (ordered) service is designed, implemented and tracked (providing the subcomponent parts).

PUC - Public Utilities Commission

The agency regulating intrastate phone service.

Rate Element

A recurring fixed charge for IEC or LEC service at the lowest level. A local loop may have multiple rate elements associated with it, which make up the fixed portion of the monthly bill. For example: Local Access, Local Mileage, Entrance facilities, Channel Termination, Interexchange, etc.

Rates and Tariffs

Standards published by AT&T, OCCs,LECs, and IECs that define service availability, cost and provisioning procedures.

RBOC - Regional Bell Operating Company

 

Rebiller - See Reseller

 

Regional Bell Operating Companies - RBOC

One of the seven "Baby Bell" Companies created by the 1982 Modified Final Judgement that specified the terms of the AT&T Divestiture. The seven RHCs include: NYNEX, Bell Atlantic, Bell South, Southwestern Bell, U.S. West, Pacific Telesis, and Ameritech. "RBOC" is sometimes used informally to refer to the Regional Holding Companies defined in the 1982 MFJ. (See Bell Operating Companies - There are 19 BOCs).

Regulators

FCC, PUC, Federal Courts (e.g. MFJ), etc.

Reseller - Also known as Rebiller

A long-distance carrier (IEC) that does not own a network, but leases bulk capacity and resells portions of it at a higher rate.

Residential Customer

An individual (non-business) telephone system subscriber.

Responsible Organization - R/O

With 800 Portability,the Number Administration Service Center (NASC) allows the RespOrg to make changes such as carrier, termination, 800 call routing (by time of day, location.) A Letter Of Agency (LOA) must be on file to change the RespOrg for each customer/account.

Slam

An end user that is PICed without their permission. An RBOC Slam Fee must be paid for each slam.

SMS - Service Management System

 

SMS Customer Record

All information related to one 800 number, effective date and time, etc.

Speed Dialing

A service to abbreviate and accelerate frequently dialed numbers.

State Tax

A collection of tax types that each state is allowed to charge. Tax jurisdiction (which state can charge tax for a call) is based on the two-out-of-three rule: where it originates, where it terminates, where it is being billed to - if two match, that state can charge the tax.

Surcharge

An additional charge on top of a base rate for a specified reason.

Switch

A device (like a DMS-250 or a PBX) that responds to originator signals and dynamically connects the caller to the desired communication destination.

Switched Access

Nondedicated local access between the customer's premise and the serving wire center which is interconnected to the company's point-of-presence for origination or termination of service.

Switched Access Service

A class of LEC services that provides the link from the customer's premise to the IEC PoP for switched circuits.

Switched Resellers

Resellers that utilize their own switching hardware (and sometimes their own lines) and the lines of other IXCs to provide long-distance service to its subscribers. They provide their own billing and service.

Switched Services

All dial up long-distance services including conventional residential and WATS (most have incremental use charges). (See Message Toll Service)

Switching Fee

A per-line fee (usually around 5$) imposed by the LEC to reprogram their switching system to change your default carrier. Subscribers must usually pay this fee when switching to a reseller. Some resellers will reimburse the subscribers for this fee.

Switchless Reseller

A reseller of long-distance services that does not utilize any of its own lines, or (switching) equipment. All actual service and equipment is handled by the IXC. Billing is usually done, by the reseller themselves, to the customer.

T1/DS-1

(Facility) The equivalent of 24 multiplexed voice grade channels. 1.544 million bits per second (1.5Mbps)

T2/DS-2

(Facility) The equivalent of 4 multiplexed T1 channels. 6.312 million bits per second (6.3Mbps)

T3/DS-3

(Facility) The equivalent of 28 multiplexed T1 channels. 44.736 million bits per second (45Mbps)

T4/DS-4

(Facility) The equivalent of 6 multiplexed T3 channels. 274.176 million bits per second (274Mbps)

Tariff

A public document filed with the FCC or a PUC that outlines services and rates. Usually, all customers are offered the same rate for a specific service, based on published constraints.

TDD - Telecommunications Device for the Deaf

Telco - Telephone Company

The local or regional telephone company that owns and operates lines to customer locations and Class 5 Central Office Switches. Telcos have connections to other COs, Tandem (Class 4 Toll) offices and may connect directly to IECs like WorldCom, AT&T, MCI, Sprint, LDDS, etc.

Third Party Billing

Use of an outside service bureau for bill processing such as: call rating, customer invoicing, collections, etc.

Time of Day Routing

Route calls based on the time the call originates. (e.g. direct morning calls to East Coast operators and afternoon calls to West Coast operators, etc.). SMS/800 supports 15 minute time intervals.

Toll

A rated call (Contrast CDR - unrated call detail record). Tolls appear on the Invoice Detail.

Toll Call

A call with incremental use (minute-by-minute) charges. (Often through a Class 4 Toll Office).

Toll Fraud

A crime in which a "hacker" obtains telecommunication services by: breaching computer security, using or selling stolen long-distance credit-card codes, or, accessing a PBX and using its communication facilities illegally. Toll Fraud is estimated to cost U.S. companies $1.2 billion/year.

Two Out Of Three Rule

When determining state tax jurisdiction, there are three locations to consider: originating station, destination station, and the location that the bill is sent to. If two out of three are the same, then that state receives the tax.

USF - Aka: Universal Service Fund Charge or Universal Service Charge This charge started on January 1, 1998 as part of the FCC overhaul of telephone fees. All companies that provide telephone service between states pay a set percentage of their previous year's billings. The charge is designed to ensure affordable access to telecommunications services for telephone customers with low incomes, telephone customers who live in areas where the cost of providing telephone service is extremely high, libraries, schools, and rural health care providers. Although all companies providing interstate telephone service are charged the same percentage of their billings, companies are allowed to recharge you for this in any way they see fit, and each company uses a different method to charge this carrier specific fee. It is normally not presented to you in such a way that you would think it is a competitive pricing issue. But it is! Some companies do not charge this fee at all, some charge a carrier specific flat fee, others charge a percentage of your interstate and international usage, while others charge a percentage of your entire bill. Although the charge the companies pay is in essence a tax, the fee on your bill is carrier specific, and is NOT a set tax. The telephone company keeps any difference between the USF fees they collect and the charge they pay to the Universal Service Fund.

Vanity Number

A specific 800 or 888 number (may spell something).

Verified Account Codes

See Account Codes. A finite list of carrier-verified, predefined Account Codes.

Voice Mail

An automatic answering service with the ability to record a message. Unlike simple answering machines, Voice mail uses a programmable computer system with options such as temporary call routing, monitoring and reporting, etc.

Voice Mail Box

The assignment of one user/number on a voice mail system.

WATS - Wide Area Telephone Service

Flat rate, or special rate pay-by-the-minute (measured) billing for a specified calling area. May be outbound or inbound (e.g. 800).

Wireless

Radio waves, cellular, satellite, microwave, etc.

WTN - Working Telephone Number

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