C

Cable Entrance Facility - CEF
    Primary entrance point for cables into the building, typically where conduits from the street end.   It usually has a framing structure for the organization of splices and cables.

Cablespan
    Name for Tellabs Cablespan 2300 equipment utilized by ELI for dialtone traffic.  Comprised of two main parts - the HDT which is located in the HUB and the RST which is located at the remote customer location.  Equipment muxes and demuxes traffic from the DS-0 level up to the DS-1 or DS-3 level and then breaks it back down.

Call
    A completed switched communication (at a specified bandwidth) between two stations on a
network. A call is originated by a  "calling party", "calling station" or "caller". The destination or
termination of a call is the "called party", "called station(s)" or  "destination node" on the network.

Call Detail Record - CDR
    An accounting record produced by Switches to track Call Type, Time, Duration, Facilities used, Originator, Destination, etc.  CDRs are used for customer billing, rate determination, network monitoring, and facility capacity planning. CDRs represent  unrated calls (to be processed by Rating) in contrast to Tolls, which are rated calls.

Call Duration
    The period of time that begins with Answer Supervision (destination off hook) and ends when
the call is terminated.

Call Processing Data - CPR
    Information sent to SMS to define specific 800 service features, such as call routing by: time of day, day of week, state of call  origination, load balancing, etc.

Call Routing Tree
    A graphical display of complex call routing decision logic.

Call Tree
    A graphical display of computer function Call sequence. Documents function usage. Used for change impact analysis.

Call Type
     (e.g. 1+, 0+, 800, etc.)

Called Station - Also known as Called Party Destination Node On The Network
    The telephone number to which a call is directed or terminated.

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 Station - Also known as Calling Party - Origination Node On The Network
     The telephone number or ANI that initiates a call.

CAP - Competitive Access Provider

CAPC - Competitive Access Provider Capacity
    The highest possible (reliable) transmission speed that can be carried on a channel, circuit or piece of equipment. Capacity  may be expressed as raw speed or net throughput.

Card Issuer Identifier Code - CIID - (pronounced "sid")
     A code issued with certain calling cards. AT&T's CIID cards cannot be used by other interexchange carriers but can be used  by LECs.

Carrier
     A telecommunications provider which owns switch equipment.

Carrier Circuit
    A higher level circuit (DS-1, DS-3, Transmission System, etc.) that has been designed to carry lower-level circuits (DS-0,  DS-1).

Carrier Facility Assignment - CFA
     An identifier for the Telco network point where an IEC connects.

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.  The ELI CIC is  802, so our customers would dial 1+ 0 + 802,  followed by 1 + area code and phone number he wants to reach.

Carrier Split
    Use of 800 service call routing features to divide 800 calls between two or more IECs. Split
may be by % allocation,  origination NPA, Time of Day, etc.

Cascade 9000
    A frame relay switch deployed by ELI in multiple locations, to support the backbone network.
Cascade company in now owned by Ascend Communications.

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

Casual Customer
     Any person or organization that dials any CIC Code. (Not necessary to pre subscribe to the carrier.)

CATV - Community Antenna TeleVision
    A community television system, served by cable and connected to a common (set of ) antenna(s). 1994 Federal legislation  may allow them to compete with LECs for telephone service (on the Information Superhighway).

CBR - Constant Bit Rate
    An ATM service category which supports a constant or guaranteed rate to transport services such as video or voice as well as circuit emulation, which requires rigorous timing control and
performance parameters.

CBUD - Call Before U Dig
    Signs often seen along fiber optic cable routes, which designate an operational management
system for protection of fiber  facilities. May have electronic geographic maps of states, counties
and city streets where the carrier has buried facilities,  upon which reported construction activities are automatically mapped. Human technicians verify that the activities do not  pose a danger to the facilities, or dispatch on-site technicians when facilities may be at risk.

CCITT - Consultant Committee on International Telephone and Telegraph
    An international organization which develops standards and defines interfaces for telecommunications. (now known as ITU).

CCS
    1) Common Channel Signaling - A method of digitally transmitting call-setup and network
control data over a special  network fully separate from the network that carries the actual call.
    2) In US telecommunications traffic engineering, it means Hundred (C) Call Seconds, and is a
unit of traffic quantity  equivalent to a phone call 100 seconds long.

CCS7 - Common Channel Signaling #7
    A signaling method in which a single channel conveys, by means of labeled message, signaling information relating to a multiplicity of circuits or calls and other information, such as that used for network management.

Cell
     1) Packet switching information grouped in units of uniform size. Cells are fixed-length packets.  (e.g. ATM 53-byte cells)
     2) A small group acting as a unit in a larger organization (e.g. one of the separate geographical areas covered by a radio  transceiver antenna in a multi-antenna cellular phone system, a spreadsheet cell, a biological cell, etc.).

Cell Relay
    Packet switching technique which uses packets of fixed length, resulting in lower processing speeds.  Also known as  BISDN and ATM.

Cellular Service Type
    Type 1 - ANI only identifies the mobile cellular system, Type 2 - ANI identifies the mobile DN placing the call, but does not  necessarily identify the true call point of origin, Roaming - Subscriber is "roaming" in another cellular network. Roaming ANI  identifies the mobile DN placing the call, but does not necessarily identify the true forwarded-call origin.

Central Office - CO
    One local Class 5 Switch with lines to customer locations. (Usually less than 100,000 telephone lines per Central Office.)  COs are usually owned and operated by LECs or BOCs. COs have connections to Tandem (Class 4 Toll Offices) and often  connect directly to other COs and IECs like AT&T, MCI, WorldCom, Sprint, etc. A CO is a major equipment center designed
to serve the communications traffic of a specific geographic area. CO coordinates are used in mileage calculations for local and interexchange service rates. A Non-Conforming CO is one that does not (yet) support Equal Access.

Central Office Terminal - COT
    Equipment used for multiplex/demultiplex and analog/digital conversion functions at the central
office end of the loop T-carrier circuit.  May be provisioned to provide line-powering or to interface with a DS-1 signal at the DSX.

Centrex
    A service that is functionally similar to a customer-premise PBX, but provided by means of
equipment located in a Central  Office, and uses that equipment to route internal calls from one
extension to another, to route incoming phone calls  directly to the appropriate extension, to
handle direct dialing of outbound calls, and to provide other PBX-like features.

CEPT - Conference on European Post and Telegraph
     A European organization which develops standards and defines interfaces for telecommunications.

CER - Cell Error Ratio
    The ratio of erred cells in a transmission in relation to the total cells sent in a transmission.
The measurement is taken over a time interval and on an in service circuit.

CFA - Customer Facility Assignment

CGA - Carrier Group Alarm
     A major alarm condition for a T1 or E1 multiplexer or DACS frame which results in channels
being taken out of service.  Normally a RED, YELLOW, or AIS condition.

Channel
    A telecommunications path (pipe) of a specific capacity (speed) between two locations in a
network. The smallest  subdivision of a circuit that provides a type of communication service;
usually a path with only one direction.

Channel Bank
    A multiplexer that merges 24 voice and/or data circuits into a single T1 (DS-1) digital
communication format.

Channel Extension / Channel Networking (Service)
    Interfaces that allow high-speed computers to communicate with remote devices at local
channel speeds (over T1/T3 lines).

Channel Service Unit / Data Service Unit - CSU / DSU
    Manages digital transmission, monitors signals for problems. Responds to Central Office commands. It performs many of the  functions that modems do, but it does not have to convert digital signals to/from analog, since the end device and the  underlying transmission facility are both digital.

Channel Termination
    The equipment (multiplexer, channelizer, etc.) required to provide a connection point for one channel.  For dedicated circuits,  there is a recurring charge rate element for each channel termination.

Channelize
     To subdivide (or break out) a broadband transmission system into multiple communication channels.

CIR - Committed Information Rate
    In a frame relay network, each PVC is assigned a Committed Information Rate, measured in bits per second. The CIR  represents the average capacity that the Port Connection should allocate to the PVC. This rate should be consistent with the  expected average traffic volume between the two sites that the PVC connects. The CIR that is assigned to a PVC cannot  exceed the speed of either the originating or terminating Port Connection.

Circuit
     A switched or dedicated communications path with a specified bandwidth (transmission speed/capacity).

Circuit Media Wire Cables
    Two Wire (not twisted), Twisted Pairs (Radio Frequency Interference Canceling), Shielded Coaxial Cable, Terrestrial  Microwave, Satellite Microwave, Fiber Optic.

Circuit Switching
    A switching method where a dedicated path is set up between the transmitter and receiver. The
connection is transparent,  meaning that the switches do not try to interpret the data.

City Pair
    Two cities between which an IEC offers long-distance service. When ordering a new dedicated
circuit or trunk group, "city  pair" NPA/NXXs are used to determine the switch location.

CLASS - Custom Local Area Signaling Service
    A grouping of optional enhancements to basic local exchange telephone service which employs
digital switching and out-of-band network-control signaling to give subscribers the ability to screen
and selectively reject, forward, trace and redial incoming calls.

Class 3 - IEC - Interexchange Carrier
    Hierarchical interconnection for Class 4 and optional Class 5 Switches

Class 4 - Tandem Office - Toll Office
    Interconnection for Class 5 Switches and long distance via Class 3 IECs. Optional direct connection to higher volume Class 4  sites. A Class 4 may also serve as a Class 5 CO.

Class 5 - Central Office -End Office
    Connection to local Customer Premise Equipment and local switching. Capacity typically is up to
100,000 lines, 1 to 10 NXX.

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

Client/Server - C/S
    A distributed computing model in which clients request data and processing from servers. Servers usually have higher  capacity than clients (but not necessarily). Client/Server exploits less expensive hardware than host-based computing, but  C/S application design and resource management must be more sophisticated. See Peer-To-Peer

CLEC - Competitive Local Exchange Carrier

CLLI (pronounced "silly") - Common Location Language Identifier
    A unique identifier assigned to LEC End Offices and Tandem (Class 4 switch) Toll Offices groups. The CLLI code is the  designation for a central office, or the area served by a central office and is a BellCore standard. Example: PTLDOR69CG0  The first four digits designate the location (city);  digits 5 & 6 are the state code, digits 7 & 8 are the CO name,  digits 9 through 11 specify equipment type.  A "T" in the eleventh field  would identify the location as a Tandem office.

Closed End
    The end of a line (such as a WATS 800 or foreign exchange line) from which all calls are directed to or from a single point.  Private lines normally have two closed ends.

CLR - Circuit Layout Record
    A physical means of displaying the path a circuit takes to get from one location to another.  Usually produced via a computer software program, or hand drawn,  and includes locations, equipment, and facilities within the circuit path.

CMSDB
     SCP 800 Number Translation Database (To POTS)

COAM
     Customer Owned and Maintained Equipment.

COB
     Close Of Business (completed by end of business day)

COCOT - Customer Owned Coin Operated Telephone
    Private pay phones leased or owned by an individual, private company or institution (not the local
telephone company).

CODEC - enCOde/DECode
    A device that converts (encodes) analog signals into a form for transmission on a digital circuit.
The digital signal is then  decoded back to analog at the receiving end of the transmission link.
Codecs allow voice and video transmission over digital  links. Codecs may also support signal
compression. (Contrast modem)

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

Collocation
    The physical placement of in-service customer telecommunications equipment at a carrier's central office, point of presence  or other network location.

COM - Continuation of Message
    An indicator used by the ATM Adaptation Layer to indicate that a particular ATM cell is a continuation of a higher layer information packet which has been segmented.

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.

Communication Link
     A system of hardware and software connecting two end users.

Companding
    Compression or expansion of encoding levels to increase signal quality when digitizing an analog
signal.

Competitive Telecommunications Association - CompTel
    An industry association of IECs that does not include AT&T, MCI or Sprint, but does include most medium-sized communications carriers. CompTel may also refer to one of the organization's
conventions.

Competitive Access Provider - CAP
    A company other than a LEC, RBOC, or AT&T that is authorized to provide access service to
customers within the  same market areas.

Compression /Decompression
    A method of encoding/decoding signals that allows transmission (or storage) of more information
than the media would  otherwise be able to support. Both compression and decompression require
processing capacity, but with many products,  the time is not noticeable.

Computer Aided Design/Computer Aided Manufacturing -CAD/CAM
    CAD - A computer application using software and high-resolution graphics for drafting, design and similar engineering  functions.
    CAM - Computer-controlled manufacturing. When CAD is connected with CAM it is sometimes
called CIM.
    CIM - Computer Integrated Manufacturing. CIM allows efficient production of small quantities of
custom-designed equipment.
    When CAD and CAM are distributed over a geographical area, significant communication network capacity may be required.

Configuration
    1. The relative arrangement, options, or connection pattern of a system and its sub component
parts/objects.
    2. The process of defining an appropriate set of collaborating hardware and software objects to solve a particular problem.

Connection
    1. A Point-To-Point Dedicated or Switched communication path.
    2. An ATM connection consists of concatenation of ATM layer links in order to provide an end-to-end information transfer  capability to access points.

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 Carriage
    The provision of regulated service pursuant to individually negotiated contracts, instead of through
    public tariffs.

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.

Converter
    A repeater that also converts from one media type to another, such as from fiber to copper, and often called a media adapter.

Coordinates Vertical and Horizontal (V&H)
     Grid points used to determine straight-line mileage between locations such as PoP, CO, etc.

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)
 
CPCS - Common Part Convergence Sublayer
    The portion of the  convergence sublayer of an AAL that remains the same regardless of the traffic type.

CPN - Calling Party Number
    New acronym for ANI that identifies the originating telephone number field in an SS7 message.

CREDFACS
    Conduit, Raceway, Equipment Ducts, and FACilitieS. Generic collective term for infrastructure used in cabling.

Cross-Aisle Tie Circuit
    An interconnection between physically separated distribution frames.

Cross Connect
    A point in a network where a circuit is connected from one facility to another by cabling between
equipment such as DSX  bays or distribution frames;  or,  is accomplished via a software command
within a piece of equipment such as a DACS  to connect one circuit to another.

CS - Convergence Sublayer
    The general procedures and functions that convert between ATM and non-ATM formats.  This describes the functions of the upper half of the AAL layer.

CSB - Client Support Bulletin
    NASC information to RespOrgs about NPA splits, etc.

CSPDN - Circuit Switched Public Data Network
    Circuit oriented public network usually based on X.25.

CSU -- Channel Service Unit.
    A device used to connect a digital phone line coming in from the phone company to network access equipment located on the customer premises. A CSU may also be built into the network interface of the network access equipment.

Customer
    An individual person or organization that purchases (orders, requests, or may be billed for) service.  A customer may be  related to an entity that pays for products. For example, a subsidiary company may have its own customer identification even  though the parent company pays all charges. A billable customer may be someone that merely accepts an operator service  call or a casual customer that dials a CIC code (like 10555) without presubscribing. A service provider or an agent may act as (or on behalf of) a customer. (Contrast with End User)

Customer Premise
     The local facility where the circuit terminates.

Customer Premise Equipment - CPE
    Communications equipment (such as PBX switches, origination/termination adapters, multiplexers, modems, codecs,  telephones, computers, etc. - but not including carrier lines) at the customer's location that connects to carriers' Products  and Services. CPE may be COAM or provided by the carrier. Primary CPE suppliers include: AT&T, Northern Telcom, NEC,  Phillips, Siemens, Erickson, etc.

Customer Record Information System - CRIS (pronounced "chris")
     A system used by many LECs to maintain customer records.

Customer Type
    Classification of customer that defines procedural rules and the availability of products, services,
features and options (e.g.  residential, commercial, reseller, carrier, etc.)

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.

Cycle - A recurring series of events
     (e.g. Business Cycle, System Life Cycle, etc.)