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Telecommunications Terminology & Acronyms

3G
3rd Generation wireless technologies such as Internet-enabled Palm Pilots

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.

Access Charge
A fee charged subscribers or other telephone companies by a local exchange carrier for the use of its local exchange networks.

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.

Analog Signal
A signaling method that uses continuous changes in the amplitude or frequency of a radio transmission to convey information.

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)

ATM
Asynchronous Transfer Mode; a cell based switching technology that supports true multimedia networking; ATM allows the class of service for information/data on the network to be specified and can emulate other telecommunications services. ATM is often used in conjunction with SONET, but may operate at any transmission rate.

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 signaling 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.

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.

Bandwidth
The capacity of a telecom line to carry signals. The necessary bandwidth is the amount of spectrum required to transmit the signal without distortion or loss of information. FCC rules require suppression of the signal outside the band to prevent interference.

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 Judgment 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.

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).

Broadband
Broadband is a descriptive term for evolving digital technologies that provide consumers a signal switched facility offering integrated access to voice, high-speed data service, video-demand services, and interactive delivery services. High capacity digital data services, generally 256 kilobytes per second or faster.

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).

Calling Party Pays
A billing method in which a wireless phone caller pays only for making calls and not for receiving them. The standard American billing system requires wireless phone customers to pay for all calls made and received on a wireless phone.

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.)

Cellular Technology
This term, often used for all wireless phones regardless of the technology they use, derives from cellular base stations that receive and transmit calls. Both cellular and PCS phones use cellular technology.

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

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
In the telecommunications arena, the term used to describe a telephone company.

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.

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)

Cramming
A practice in which customers are billed for enhanced features such as voice mail, caller-ID and call-waiting that they have not ordered.

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.

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

Dedicated Access Line (DAL)
A non-switched circuit from the customer to a carrier.

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 Around
Long distance services that require consumers to dial a long-distance provider’s access code (or "10-10" number) before dialing a long-distance number to bypass or "dial around" the consumer’s chosen long-distance carrier in order to get a better rate.

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.

Digital Switch
A computer-based machine for establishing and managing on-demand telecommunicationssuch as a telephone call.

Direct Distance Dialing (DDD)
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.

Directory Assistance (DA)
Phone Number Lookup Service whereby operators assist customers in obtaining the telephone number(s) they wish to call.

DS-1 and DS-3
Digital System 1 and 3; Digital carrier services, or telecommunications links; DS-1 provides1.544 megabytes per second or 24 phone calls (same as T-1), DS-3 is equivalent to 28 DS-1s or 45 megabytes per second of capacity.

DSL (also ADSL, HDSL, or xDSL)
Digital Subscriber Line; a broadband connection provided over telephone lines.

E-Mail
Also called electronic mail, refers to messages sent over the Internet. E-mail can be sent and received via newer types of wireless phones, but you generally need to have a specific e-mail account.

Enhanced Service Providers
A for-profit business that offers to transmit voice and data messages and simultaneously adds value to the messages it transmits. Examples include telephone answering services, alarm/security companies and transaction processing companies.

Equal Access
(AT&T Divestiture - 1982 Modified Final Judgment) 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.)

Federal Communications Commission (FCC)
Regulates interstate communications: licenses, rates, tariffs, standards, limitations, etc. Appointed by U.S. President.

Frequency Modulation (FM)
A signaling method that varies the carrier frequency in proportion to the amplitude of the modulating signal.

Global Positioning System (GPS)
A US satellite system that lets those on the ground, on the water or in the air determine their position with extreme accuracy using GPS receivers.

Interactive Video Data Service (IVDS)
A communication system, operating over a short distance, that allows nearly instantaneous two-way responses by using a hand-held device at a fixed location. Viewer participation in game shows, distance learning and e-mail on computer networks are examples.

Interexchange
Communication between two different LATAs.

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

Instructional Television Fixed Service (ITFS)
A service provided by one or more fixed microwave stations operated by an educational organization and used to transmit instructional information to fixed locations.

ISP
Internet Service Provider; any firm that sells Internet services such as access, web hosting, electronic mail. ISPs may own their own network infrastructure or may lease it from other telecommunications providers.

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 Miles Interexchange Carrier (Long Distance) Miles
On a Price Quote, the coordinates of Location A and Location B are used to calculate mileage-dependent line charges.

LAN
Local Area Network; a private computer network that physically connects devices within a building. A WAN connects multiple sites via telecommunication.

Landline
Traditional wired phone service.

Land Mobile Service
A public or private radio service providing two-way communication, paging and radio signaling on land.

LATA
Local Access Transport Areas (200 in the U.S.). A geographic service area defined in the AT&T Modified Final Judgment. 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 Charges
Charges that are the responsibility of the local exchange carrier.

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. A CLEC is a “competitive” LEC, or a new firm entering the market in competition with the ILEC, which is the “incumbent” LEC, the established telephone company.

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.

Network
Any connection of two or more computers that enables them to communicate. Networks may include transmission devices, servers, cables, routers and satellites. The phone network is the total infrastructure for transmitting phone messages.

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."

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.

Number Portability
A term used to describe the capability of individuals, businesses and organizations to retain their existing telephone number(s) – and the same quality of service – when switching to a new local service provider.

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).

OC-1, OC-3, etc.
Optical Carrier; OC designates an optical fiber based telecommunications link that is part of the synchronous optical hierarchy (see SONET). OC-1 is equivalent to a DS-3, OC-3 provide 155.52 mbps of bandwidth or 2,016 voice-grade channels, OC-12 provides 622 mbps or over 8,000 voice grade channels, OC-48 provides nearly 2,5000 mbps or over 32,000 voice-grade channels.

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)
A common carrier that provides services from public phones, including payphones and those in hotels/motels.

Packet (also frame or cell)
A unit of data communication, generally consisting of an address and data payload. Packets, frames, and cells differ the ways they are assembled and routed across the network, and imply different network technologies (e.g., ATM uses cells, T-1 uses frames).

POP
Point of Presence; an interconnection point between a LEC and an IXC or ISP.

Paging System
A one-way mobile radio service where a user carries a small, lightweight miniature radio receiver capable of responding to coded signals. These devices, called "pagers," emit an audible signal, vibrate or do both when activated by an incoming message.

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

Personal Communications Service (PCS)
Any of several types of wireless, voice and/or data communications systems, typically incorporating digital technology. PCS licenses are most often used to provide services similar to advanced cellular mobile or paging services. However, PCS can also be used to provide other wireless communications services, including services that allow people to place and receive communications while away from their home or office, as well as wireless communications to homes, office buildings and other fixed locations.

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
National Access Fee, LD Line Charge, Presubscribed Interexchange Carrier Charge, Presubscribed Line Charge, Regulatory Related Charge, FCC Primary Carrier 1st Line, or Carrier Line Charge.

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.

Presubscribed Interexchange Charge (PICC)
The charge the local exchange company assesses the long distance company when a consumer picks it as his or her long distance carrier.

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 Judgment 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.

Roaming
The use of a wireless phone outside of the "home" service area defined by a service provider. Higher per-minute rates are usually charged for calls made or received while roaming. Long distance rates and a daily access fee may also apply.

Satellite
A radio relay station that orbits the earth. A complete satellite communications system also includes earth stations that communicate with each other via the satellite. The satellite receives a signal transmitted by an originating earth station and retransmits that signal to the destination earth station(s). Satellites are used to transmit telephone, television and data signals originated by common carriers, broadcasters and distributors of cable TV program material.

Service Plan
The rate plan you select when choosing a wireless phone service. A service plan typically consists of a monthly base rate for access to the system and a fixed amount of minutes per month.

Service Provider
A telecommunications provider that owns circuit switching equipment.

Slamming
The term used to describe what occurs when a customer’s long distance service is switched from one long distance company to another without the customer’s permission. Such unauthorized switching violates FCC rules.

SMS
Service Management System.

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

SONET
Synchronous Optical Network; very high capacity, optical fiber based telecommunications network system, SONET has a ring architecture which make it very reliable; typically used in the core network of telecommunications service providers.

Spectrum
The range of electromagnetic radio frequencies used in the transmission of sound, data and television.

Spread Spectrum
A “frequency-less” (as opposed to traditional radio) wireless telecommunications technology that allows wireless connections to be very clear and secure.

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.

Subscriber Line Charge (SLC)
A monthly fee paid by telephone subscribers that is used to compensate the local telephone company for part of the cost of installation and maintenance of the telephone wire, poles and other facilities that link your home to the telephone network. These wires, poles and other facilities are referred to as the "local loop." The SLC is one component of access charges.

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
Non-dedicated 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 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) A digital telecommunications link that supports 24 voice-grade channels and provides 1.544 megabytes per second of bandwidth. T-1 is equivalent to DS-1 but is specifically carried over copper twisted pair wire.

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
The public documents 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.

TCP/IP (or just IP)
Transmission control Protocol/Internet Protocol; the core technologies of the Internet that specify how devices are addressed (IP) and how connections between these devices are set up/maintained (TCP, or associated protocol UDP (User Datagram Protocol)). TCP(UDP)/IP works in conjunction with various protocols for routing data across the internet and protocols for applications such as the worldwide web, e-mail and directories.

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.

Telecommunications Relay Service (TRS)
A free service that enables persons with TTYs, individuals who use sign language and people who have speech disabilities to use telephone services by having a third party transmit and translate the call.

Telephony
The word used to describe the science of transmitting voice over a telecommunications network.

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.

TTY
A type of machine that allows people with hearing or speech disabilities to communicate over the phone using a keyboard and a viewing screen. Also known as TDD.

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.

Unbundling
The term used to describe the access provided by local exchange carriers so that other service providers can buy or lease portions of its network elements, such as interconnection loops, to serve subscribers.

Universal Service
The financial mechanism which helps compensate telephone companies or other communications entities for providing access to telecommunications services at reasonable and affordable rates throughout the country, including rural, insular and high costs areas, and to public institutions. Companies, not consumers, are required by law to contribute to this fund. The law does not prohibit companies from passing this charge on to customers.

USF
Universal Service Fund Charge or Universal Service Charge, Carrier Universal Service Charge, Federal Universal Service Fund Surcharge

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.

Very High Frequency (VHF)
The part of the radio spectrum from 30 to 300 megahertz, which includes TV Channels 2-13, the FM broadcast band and some marine, aviation and land mobile services.

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.

Capacity of Various Telecommunications Technologies

Technology Channels Uncompressed Transmission Rate
Analog telephone 1 2400 bps (bits per second)
DS-0 1 64 kbps (thousand bps)
Basic Rate ISDN 2 128 kbps
Primary Rate ISDN 23 1.472 mbps (million bps)
DS-1 (T-1) 24 1.544 mbps
DSL/ADSL Various Various (typical 1-8 mbps)
Ethernet N/A* 10 mbps
Token Ring N/A 12 mbps
DS-3 (T-3) 672 45 mbps
OC-1 672 51.84 mbps
FDDI N/A 100 mbps
Ethernet N/A 100 mbps
OC-3 2,016 155.52 mbps
OC-12 8,064 622.08 mbps
OC-48 32,256 2,488.32 mbps
*Methods used for computer communications are "unchannelized."

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