Access Line - A telephone circuit which connects a customer location to a CO

ANI- Automatic Number Identification = Also called WTN - Telephone number in the format: NPA-NXX-XXXX.  Every ANI or telephone number resides in a specific CO. There are three parts to an ANI: the 3-digit area code (NPA), the 3-digit central office code (NXX) and the 4-digit subscriber number (XXXX).  Also referred to as a POTS number. 

AT&T - American Telephone and Telegraph - formed in 1885 as a subsidiary of American Bell for the purpose of developing long distance service.

Area Code - A three digit number identifying more than 161 geographical areas of the United State and Canada which permits direct distance dialing on the telephone system.  (NPA/Numbering Plan Area)

Bands A, B, & C - The areas of a LATA that are designated by the LEC. They are assigned by proximity to the CO, A being the closest, B as the middle distance, and C as the farthest.  In LATA 358 (Chicago and surrounding suburbs) this can refer to 2 areas:  how far the call travels between COs (determines how much is paid per minute during a call) and how far the customer premise is from the CO (determines monthly service charges).   

Bandwidth - The capacity of a communications channel, referring to the range of frequencies (vibrations per second).  Bandwidth also refers to the digital transmission speed of a channel measured in bits per second.

Blackberry - a cutting edge communication tool that allows the user to access Internet, cellular, and email from the same device. 

BOC - Bell Operating Company - Any of 22 local telephone companies which were owned by AT&T prior to the 1984 divestiture.  They became independent operations and were originally grouped into one of seven regional “holding companies” known as RBOCs (Regional Bell Operating Companies)

Bonded T1 - a standard T1 that is connected together with another T1 to increase bandwidth

BTN- Billing Telephone Number, the main number an account is billed under. WTNs fall under a BTN and comprise that BTN’s usage and monthly charges. The BTN is often synonymous with the customer account number.  Carrier Access Code - same as PIC code - unique code assigned to individual LD carriers to identify each carrier and tell the local phone company which LD carrier to hand a long distance call to. 

CDR - Call Detail Record - A record that contains data unique to a specific call. The calling and called numbers are registered first. When the call is answered, an answer entry registers the time until a disconnect entry stops the clock.  This information is used to rate the call for charges.

CFV - Call Forward Variable, a programmable forwarding feature, usually *72, 72# to activate, *73, 73# to deactivate.  This allows a call to be forwarded from one location to another. 

CID - Caller Identification - Automatically identifies and displays the originating number of an incoming call on the customer’s equipment during the ringing cycle.  The main purpose is to screen incoming calls.

CLEC - Competitive Local Exchange Carrier, a smaller LEC, possibly a reseller of LEC service. Examples include AT&T, XO, McleodUSA, Cimco and others.

CO - Central Office - old terminology is Wire Center - is a LEC switching facility which provides a communication channel to every telephone in its serving area. Each CO is owned, operated, and maintained by a LEC. Each CO is assigned one or more NXX exchanges or prefixes.

CPE - Customer Premise Equipment - Equipment that resides on customer premise.  Could be telephone equipment, computer equipment, printers etc.

CSR - Customer Service Records - Records showing exactly what phone service a customer is being billed for.  Written in standard codes known as USOCs.  Universal Service Order Code

CSU - Channel Service Unit, equipment that is required on a T1 line and functions like a circuit breaker to protect customer equipment

Dedicated T1- a permanently assigned path for data/voice, etc. from the customer premise to the IXCs POP or switch

Dial Tone - Produced by the CO to indicate that a line is open

 DIA - Dedicated Internet Access - Dedicated T1 to the Internet at the speed of 1.544 Mbps 

DID - Direct Inward Dial - Number that is used to route an incoming call.  Normally lands on a Prime T1 (PRI) or analog DID trunks.  Used when a business wants to avoid calls being answered by the switchboard and go directly to an individual. 

DIOD - Direct Inward/Outward Dial - Allows a person to accept calls directly in or to dial out with the same phone number. Used in a DID situation where DOD call appearances will show on CID.

Divestiture - The January 1, 1984 breakup of the Bell System into AT&T (with long distance and equipment divisions, among others) and the local BOCs.  Also known as MFJ (Modified Final Judgment).

DLR - Design Layout Request - Request submitted to SBC to determine the route calls will take to a location that currently does not exist - ie. Lombard Westin.

DMARC - Point of demarcation, the point at which the LEC circuit terminates at the customer premises. Also, that point at which the LEC responsibility ends.

DNIS - Dialed Number Identification Service - DNIS digits are codes used by an 800 number owner to designate a specific purpose for a particular 800 number or specific department which the incoming call should be transferred

DOD - Direct Outward Dial - Service that allows a person to dial directly out of a PRI or analog DIOD trunk. 

 DSL - Digital Subscriber Line -  

DSU - Data Service Unit - Equipment on customer premise end of a T1 that performs signaling functions between the DSU and the telephone company CO.  Combined with the CSU it performs conversion of customer’s data stream to bipolar format for transmission.

DSO - Digital Service Level 0 - Regular phone line. Math equation = 8,000 samples per second X 8 bits per sample = 64,000 bits per second or 64 Kilobits per second or 64 Kbps (DS0). A 56Kbps line is 64,000 - 8,000 framing bits for signaling. This used to be commonly used for digital data transmission. 

DS1 - Digital Service Level 1 - Synonym: T1 - A channel with the capacity of 24 DS0s. Math equation = 64K X 24 channels = 1,544 Kilobits per second (Kbps) or 1.544 Megabits per second (Mbps). 

DS3 - Digital Service Level 3 - Channel with capacity of 28 DS1s (T1s), or 45 Mbps per second. Synonym: T3 Math equation is 64 kbps X 24 channels = 1.544 Mbps (T1 speed) X 28 T1s = 43,232 Kbps or 43.232 Mbps. Number is rounded up to 45 Mbps 

DSLAM- Digital Subscriber Line Access Multiplier - allows DSL to function at the CO

FCC - Federal Communications Commission - Federal regulatory body consisting of seven commissioners appointed by the President with the power to regulate all interstate and foreign electrical communications systems originating in the US including radio, TV, telephone and cable systems.

Fiber Optics - High speed transmission medium using light to send voice and data through a flexible bundle of glass fibers.

FOC- Firm Order Commitment - The FOC date is the date the LEC will commit to completing their portion of an installation.

Hunt - a feature that allows an incoming call to roll through the phone lines to the next open line 

ILEC - Incumbent Local Exchange Carrier - examples include SBC, Verizon, Bell South

IntraLATA - Calls which originate and terminate in the same local access and transport areas

Intrastate - Calls which originate and terminate interlata and within the same state

InterLATA - Calls which originate and terminate in different LATAs. All LD calls are interLATA.

IOT- Inter-Office Trunks - a single high -capacity circuit between the two points where the COs signals and establish communication connections.

IP - Internet Protocol - transmission signaling that allows data to travel over the Internet.

ISDN - Integrated Services Digital Network - A technology and set of standards that enables users to send multiple simultaneous voice, data and video calls over few channels than otherwise needed.  ISDN establishes a separate link for call set-up and control by signaling information outside the calls physical circuit (out of band signaling) across public telephone networks.

IXC - Inter-exchange Carrier - Long Distance Carrier = provider of long distance service between LATAs.

LAN - Local Area Network - Network of locations within a customer premise or multiple customer locations within the same LATA

LATA - Local Access and Transport Area - The divestiture of AT&T established 161 geographically defined services areas called LATAs.  Local telephone companies were not allowed to provide service outside their LATA.  Calls within the LATA are called IntraLATA.

LD - Long Distance - abbreviation

LEC - Local Exchange Carrier - local phone company, usually the ILEC

MAC - Move, Add, or Change - generally an order to make a change in phone service.  This can refer to telephone company changes or equipment programming changes.

Mbps = Mega bits per second.  Math equation is 1,000 kbps

MWI - Message Waiting Indicator - Flashing light on properly equipped telephone handset or stutter dial tone when line is picked up.  This is delivered by either the phone company or the equipment and software within an internal voice mail system.

NPA - Numbering Plan Area - Commonly known as the area code - A geographical division within which no two telephones will have the same 7-digit number. The NPA identifies the geographic area within the country to which the call is routed.

NXX - central office code or exchange area for telephone service. There may be more than one central office within the NPA but there must be at least one central office in every NPA.  A call between any two points within an NXX is a local call.  Multiple NXXs can be served by a single central office.

NPA/NXX - Numbers given to vendors to determine pricing on Internet T1s, end points on point-to-point T1s etc.

OPT-E-MAN – Optical Ethernet Metropolitan Area Network - A switched Ethernet service that connects LANs within the same metro area with flexible bandwidth options from 5 Mbps to 1 Gbps.

PBX- Private Branch Exchange - a voice switching system serving an organization usually located on the organization’s premise that provides services for multiple users.

PIC- Primary Inter-exchange Carrier - technical term for long distance carrier

POP - Point Of Presence - a physical location within a LATA where an IXCs circuits connect with the LECs local tandem serving the LATA. Internet access points are known as Internet POPs.

POTS- Plain Old Telephone Service - Regular phone service

PRI - Primary Rate Interface - Voice service that is attached to a T1 for the purpose of providing an efficient, cost-effective method of making and accepting phone calls.  There are 23 channels available for calls on a PRI and one channel to direct the inbound or outbound direction of a phone call.

PSTN - Public Switched Telephone Network - A public switched telephone network denotes those portions of the LEC and IXC networks that provide public switched telephone network services

PUC - Public Utility Commission - Government regulatory body that regulates the amount of fees that can be charged by the LEC.

RBOC - Regional Bell Operating Company - One of the seven original Bell “holding companies” created by the 1984 divestiture. The Midwest RBOC was Ameritech and consisted of Wisconsin Bell, Illinois Bell, Indiana Bell, Michigan Bell and Ohio Bell. The seven RBOCs were Ameritech, Bell Atlantic, Bell South, Nynex, Pacific Telephone, US West and Southwest Bell.

RFP - Request for Proposal - Customer request for a proposal from vendors for a new or upgraded service or equipment.

Resp Org - Responsible Organization - Organization that is responsible and allowed to make changes to the national toll-free and long distance databases

V/M - Voice mail

VoIP - Voice over Internet Protocol

VPN- Virtual Private Network

WAN - Wide Area Network - A network that connects widely separated LANS over private lines, VPNs or public networks such as frame relay

WiFi - Wireless Fidelity - Internal wireless internet at a customer premise

Wireless Broadband - Internet service delivered to a premise, wire-free.


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