Telco Glossary of Terms

Access gateway
Equipment used to provide the electronic "bridge" from the public switched telephone network (PSTN) to an Internet protocol (IP) network.

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.

ANI (Automatic Number Identification)
The number transmitted through the network identifying the calling party.

ARIN (American Registry for Internet Numbers)
A non-profit organization established for the purpose of administration and registration of Internet Protocol (IP) numbers.

ATM (Asynchronous Transfer Mode)
A high-speed switching technique that uses fixed size cells to transmit voice, data and video.

B8ZS (Bipolar Eight-Zero Substitution)
A T1 line coding scheme, also known as Clear Channel, that operates at 64Kbps by sending a string of eight zeros with a deliberate bipolar violation which maintains line synchronization.

CAC (Carrier Access Code)
A dialing sequence used by the general public to access a preferred provider of service.

CARE (Customer Account Record Exchange)
The process of exchanging customer account information between local and long distance carriers. Every time a local carrier signs up a new customer, or every time an existing customer changes their PIC code, thereby changing their long distance carrier, the local carrier is responsible for notifying the long distance carrier. This applies even when the customer is keeping their current LD carrier while changing local carrier: the local carrier is still supposed to notify the LD carrier.

Carrier
A telecommunications provider which owns switch equipment.

Casual PICing
This is when the customer has chosen one primary long distance carrier (the long distance carrier they are "pic'd" to), but occasionally wants to make a call using another long distance carrier. In order to route the call through the alternative long distance carrier, the customer dials the carrier's PIC code before entering the telephone number. This is exactly the process for all those "Dial 10221" commercials. Because the customer does not sign up with this alternative carrier, they are only "casually" picing them. Some long distance carriers will not accept casual picing, and will only let you use them if you have pre-registered with them (like Cable & Wireless).

CCB (Common Carrier Bureau)
A branch of the FCC that monitors the telephone industry.

Central Office Switch
A switch used to provide telecommunications services including (1) End Office Switches which are Class 5 switches from which end-user Exchange Services are directly connected and offered, and (2) Tandem Office Switches which are Class 4 switches which are used to connect and switch trunk circuits between and among central office switches. Central office switches may be employed as combination end office/tandem office switches (combination Class 5/Class 4).

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

CFA (Connecting Facility Assignment)
Long Distance Carriers must give Local Access Carriers (TelePacific) "CFA", which are directions about where specifically on our interconnecting equipment to physically put the circuit.

Channel Bank
An interface device that multiplexes multiple channels onto an analog or digital carrier.

CIC (Carrier Identification Codes)
CICs provide routing and billing information for calls from end users via trunk-side connections to inter-exchange carriers and other entities.

Circuit
A communications link between two or more points.

CLASS (Custom Local Area Signaling Services)
Consists of number-translation services, such as call-forwarding and caller identification, available within a LATA.

CLC (Competitive Local Carrier)
The same thing as a CLEC.

CLEC (Competitive Local Exchange Carrier)
Any company or person authorized to provide local exchange services in competition with an ILEC. The CPUC's (California Public Utility Commission's) official definition is " Competitive Local Carrier (CLC) means a common carrier that is issued a Certificate of Public Convenience and necessity (CPCN) after the effective date of July 24, 1995, to provide local exchange telecommunications service for a geographical area specified by such carrier. There are two CLEC types: Facilities-based and Non-facilities-based, see definitions.

CLLICODE (Common Language Location Identifier) - pronounced "Silly Code"
A code, which identifies a customer at a physical address. (All codes are of an abbreviation for the city, state, an identifier for that particular building, and an identifier for the customer on a particular floor.)

Clocking (a.k.a Synchronization)
A network function that keeps transmission interfaces and customer premise equipment in step with one another to prevent the loss of the signal. Channel Synchronization is created by the CSU/DSU at each end of the circuit. Network Synchronization is created by digital communications links within the service provider's network.

CO (Central Office)
A LEC (Local Exchange Carrier) office that has a switch.

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.

CPCN (Certificate of Public Convenience and Necessity)
A certificate that must be filed by every CLEC with the CPUC.

CPE
Customer Provided Equipment

CSU or CSU/DSU (Channel Service Unit/Data Service Unit)
A device to terminate a digital channel on a customer's premise. It performs certain line coding, line-conditioning and equalization functions, and responds to loop-back commands sent from the central office. A CSU sits between the digital line coming in from the central office and devices such as channel banks or data communications devices and is found in every digital link and allows the transfer of data at a range greater than 56 Kbps.
Demarcation point between the wiring that comes in from the local telephone company and the wiring you install to hook up your equipment or system to the CPE.

Dedicated Line
A private line leased from a telecommunications carrier.

DEMARC
The physical and electrical boundary between an end user's telecommunication equipment and the telecommunications network. The demarcation point establishes point of ownership and accountability.

DID (Direct Inward Dialing)
A service offered by telephone companies which allows the last 3 or 4 digits of a phone number to be transmitted to the destination exchange.
For example, a company could have 10 incoming lines, all with the number 234 000. If a caller dials 234 697, the call is sent to 234 000 (the company's exchange), and the digits 697 are transmitted. The company's exchange then routes the call to extension 697. This gives the impression of 1000 direct dial lines, whereas in fact there are only 10. Obviously, only 10 at a time can be used.

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.

DS-0 (Digital Signal Level 0)
A framing specification used in transmitting digital signals over a single channel of a T-1 facility at 64 Kbps.

DS-1 (Digital Signal Level 1)
A framing specification used in transmitting digital signals at 1.544 Mbps over a T-1 facility (U.S.) or at 2.108 Mbps over an E-1 (Europe).

DS-3 (Digital Signal Level 3)
A framing specification used in transmitting digital signals at 44.736 Mbps over a T-3 facility.

E1
The European standard equivalent of a DS-1 with the capacity to transmit information at speeds of up to 2.048 Mbps.

E3
The European standard equivalent of a DS-3 with the capacity to transmit information at speeds of up to 34.364 Mbps.

End Carrier
The local carrier who terminates the call to the end user.

ESF (Extended Superframe Format)
T-1 carrier framing format that provides 64kb clear channel capability, error checking, 16-state signaling, and other data transmission features.

EUCL (End User Common Line Charge)
A FCC tariff term defined in FCC Rules 69.104 as follows: "A charge that is expressed in dollars and cents per line per month shall be assessed upon end users that subscribe to local exchange telephone service, Centrex or semi-public coin telephone service to the extent they do not pay carrier common line charges. Such charge EUCL shall be assessed for each line between the premises of an end user and a Class 5 office that is or may be used for local exchange service transmissions. Each Single Line Service is charged one CALC or EUCL. The amount varies by state."

Exchange Area
Geographically bounded areas that a LATA is divided into.

Extended Demarc
A demarcation point that is extended beyond the MPOE (Minimum Point of Entry).

Facilities-based CLEC
When a CLEC utilizes unbundled network elements from the LEC and/or provides facilities such as its own switch or transmission media. The CPUC's definition is: those CLECs who directly own, control, operate, or manage conduits, ducts, poles, wires, cables, instruments, switches, appurtenances, or appliances in connection with or to facilitate communications within the local exchange portion of the public switched network.

FCC (Federal Communications Commission)
The government agency that regulations telecommunications and other broadcast medium. www.fcc.gov

FOC
Firm Order Commitment

ICB (Individual Case Basis)
Unusual products often require an ICB to determine the pricing. Marketing supports this.

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

IEC
Interexchange Carrier

ILEC (Incumbent Local Exchange Company)
Companies such as Pacbell and GTE.

INC (Industry Numbering Committee)
An industry forum sponsored by the Alliance of Telecommunications Industry Solutions (ATIS). It provides an open forum to address and resolve industry-wide issues associated with the planning, administration, allocation, assignment and use of numbering resources and related dialing considerations for public telecommunications within the North American Numbering Plan (NANP) area. INC documents are available from: www.atis.org/atis/clc/inc/incdocs.htm. (npagdln.doc, INC Documents, http://www.atis.org/atis/clc/ic/incdocs.html)

Independent LEC (Independent Local Exchange Carrier)
Refers to non- "Ma" Bell Companies, such as GTE.

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

Intrastate
Communications inside one state.

Interstate
Communications between states.

ISDN (Integrated Services Digital Network)
A standard digital network that lets users send voice, data and video over one telephone line from a common network interface.

IXC (InterExchange Carrier)
Abbreviation for any long distance carrier. IEC is another abbreviation favored by LECs.

LAN (Local Area Network)
A data communications network that is geographically limited (typically to a 1 km radius) allowing easy interconnection of terminals, microprocessors and computers within adjacent buildings. Ethernet and FDDI are examples of standard LANs.
Because the network is known to cover only a small area, optimizations can be made in the network signal protocols that permit data rates up to 100Mb/s.

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 (Local Exchange Company)
Refers to companies such as SBC, Pacbell or GTE.

LERG (Local Exchange Routing Guide)
The LERG contains information about the current network configuration and scheduled changes within the local exchange providers' networks. The LERG is primarily designed to be used for routing of interLATA calls by inter-exchange carriers. The LERG informs telecom companies which end office or tandem office the NNX resides in and how calls should be routed and rated so that they can properly terminate to the appropriate telephone number at the proper rate.

LNP (Local Number Portability)
LNP is the ability of end users to retain their existing telephone numbers when remaining at a location, or changing their location but staying within the same geographical exchange area served by the initial carrier's serving central office, regardless of the LEC or CLC selected. LNP is also referred to as Service Provider Portability.

LOA (Letter of Agency)
This is exchanged between telecomm companies, or between a customer and a telecomm company granting permission for the receiver to install telecomm service to the sender.

Locality
Within each rate center there may be more than one "locality" - locality usually denotes a sub-city name such as the "called-from" place appearing on a customer's bill, to a rate center, to the exchange area that the NXX is identified with in a local tariff. Localities that are associated with specific rate centers can be looked up in section 6 of the LERG.

Local Loop
The local loop is the telephone line that runs from the local Telephone Company to the end user's premise. The local loop can be made up of fiber, copper or wireless media. Same as local exchange loop facility whose formal definition is "known as a basic level network access channel, local exchange loop facility means a transmission path capable of delivering analog voice grade signals or digital signals at less than 1.544 Mbps between the network interface at a customer's premises and the main distribution frame or any other point of interconnection to the LEC network."

LRN (Local Routing Number)
A 10-digit code that represents a specific carrier. This code is "attached" to each phone number to indicate which "carrier" the phone number currently is subscribed with for routing purposes. Created for the LNP process, when a customer switches carriers, the new carrier's LRN replaces the old.

LSO
Local Serving Office

LSP (Local Service Provider)
A term intended to encompass all companies providing dial tone to end users, including but not limited to Incumbent Local Exchange Carriers (ILEC), Alternative Local Exchange Carriers (ALEC) and Private Branch Exchange (PBX) providers.in

LTA (Leased Transport Area)
Demarcation point for LEC's and CLEC's to terminate customer leased carrier circuits within a carrier nuetral facility.

MPOE
Minimum Point of Entry

Multiplexing or Mux
Multiplexing is a technique whereby multiple devices can share a telephone line. With multiplexing, users do not have to lese individual telephones for each computer that wishes to communicate. T-1 multiplexers enable 24 devices to share one telephone line.

NANPA (North American Numbering Plan Administration)

NANP (North American Numbering Plan)
A numbering architecture in which every station in the area served by the plan is identified by a unique ten-digit address consisting of a three-digit NPA code, a three digit central office code of the form NNX/NXX, and a four-digit line number of the form XXXX.

NAT (Network Address Translation)
A hardware device currently being developed and used to extend the Internet addresses already in use. NAT has been suggested as an alternative to adopting IPv6 (IPng). It allows duplicate IP addresses to be used within a corporation and unique addresses outside.

NID (Network Interface Device)
The point of demarcation between the end user's inside wiring and LEC's facilities. Same as a NIU (Network Interface Unit).

NIU (Network Interface Unit)
Same as a NID (Network Interface Device), it serves as the point of demarcation between the local exchange carrier network and the customer's premise. It is required to be placed at the MPOE (minimum point of entry) which is typically in the basement, first floor telco room, garage, or even outside the building. NIUs are multi-functional devices, which include a protector block to prevent high-voltage surges from affecting premise equipment and inside wiring. It also usually allows the carrier to initiate a loop-test back from the central office to test the integrity of the local loop. A local exchange carrier will never install an NIU at an extended demarc - this is in their tariffs.

Non-Facilities Based CLECs
Those CLECs which do not directly own, control, operate, or manage conduits, ducts, poles, wires, cables, instruments, switches, appurtenances or appliances in connection with or to facilitate communications within the local exchange portion of the public switched network.

Non-published Service
The CPUC considers non-published service to be when a subscriber requests that their name, address, and telephone number not be listed in any telephone directory, street address directory, or in the directory assistance records available to the general public (411).

NPA (Numbering Plan Area also called area code)
An NPA is the 3-digit code that occupies the A, B, and C positions in the 10-digit NANP format that applies throughout the area served by the NANP. NPAs are of the form NXX, where N represents the digits 2-9 and X represents any digit 0-9. In the NANP, NPAs are classified as either geographic or non-geographic.

NPAC (Number Portability Administration Center)
A center, which supports the implementation of Local Number Portability (LNP).

NPAC SMS (Number Portability Administration Center Service Management System)
NPAC's system that manages the porting of telephone numbers from one service provider to another.

NXX
N is any digit 2 through 9, X is any digit 0 through 9 (800 possible combinations). Also known as CO codes, or DRD (destination code) once entered into the RDBS records.

NXX Service Area
The geographically-bounded area designated as the area within which a LEC or CLC may provide local exchange telecommunication services bearing a particular NPA-NXX designation.

OCN (Operating Company Number)
Assignments must uniquely identify the applicant. Must have a CO number to get this, but prior to a CO number you can use a NECA assigned number called a Company Code by calling NECA at 201-884-8355. To get an OCN call NECA at 973-884-8355.

PBX (Private Branch Exchange)
PBXs are computerized on site telephone systems located at commercial premises. They route calls both within an organization, and from the outside world to people within the organization.

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.

Port
When used as a noun, a port (also known as a basic level network access channel connection) is the interface between the local loop and the appropriate LEC Central Office switching equipment.

POTS
Plain Old Telephone Service

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

PSAP (Public Safety Answering Point)
The central point where the 911 call is received and responded to.

PSTN (Public Switched Telecommunications Network)
The PSTN is composed of all transmission and switching facilities and signal processors supplied and operated by all telecommunications common carriers for use by the public. Every station on the PSTN is capable of being accessed from every other station on the PSTN.

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).

Router
A device, with routing intelligence, that connects parts of local and remote networks together. Because they use routing tables to look up addresses for each message, routers introduce delays into networks.

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

Service Provider
Any entity that is authorized, as appropriate, by local, state, federal, or other governmental authorities within the area served by the NANP to provide communications services to the public. Same as "Telecommunications Service Provider".

Service Territory
The area in which a CLC is authorized to provide service.

SONET (Synchronous Optical Network)
A standard for transmitting high-speed digital bits over fiber optic cabling. Telephone companies use SONET to transmit data from multiple customers.

SS7 (Signaling System 7)
The signaling protocol, Version 7, of the CCS network, based upon American National Standards Institute (ANSI) standards, which allows all carriers' networks to work together. Protocols are: CCS is common channel signaling, which allows signals to be sent in both directions, which results in faster speeds.

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)

TDM (Time Division Multiplexing)
The subdivision of a transmission circuit into two or more separate circuits by assigning a given circuit successively to several different users at different times.