Interexchange carrier
Encyclopedia
An Interexchange Carrier (IXC) is a U.S. legal and regulatory term for a telecommunication
s company, commonly called a long-distance telephone company, such as MCI
(before its absorption by Verizon
), Sprint and the former AT&T
(before its merger with SBC in 2005) in the United States. It is defined as any carrier that provides inter-LATA communication, where a LATA is a local access and transport area
.
An IXC carries traffic, usually voice traffic, between telephone exchange
s. Telephone exchanges are usually identified in the United States by the three-digit area code (NPA) and the first three digits of the phone number (NPA-NXX). Different exchanges are generally in different geographic locations, such as separate central offices (COs, also called "wire centers").
IXCs used to carry voice traffic on analog lines
, but these days, most voice traffic is digitized. Therefore, voice traffic is more typically a data stream. These voice data streams therefore can be intermixed with data traffic, too, such as uplinks for DSL. Most commonly, links between an IXCs and COs are ATM
links carried on optical fiber
.
s. The interexchange carrier to which calls from a subscriber line are routed by default is known as the Presubscribed Interexchange Carrier (PIC). To give telephone users the possibility of opting for a different carrier on a call-by-call basis, Carrier Access Codes (CAC) were devised. These consist of the digits 101 followed by the four-digit CIC. The CAC is dialled as a prefix immediately before dialing a long-distance phone number.
In popular usage, CACs are often referred to as "dial-around codes" (because they allow dialing around the PIC). Sometimes they are even called "PIC codes", though this term is inaccurate, since the code is being used to avoid the PIC, not to use its services.
When CICs were first introduced in 1983, they were only three digits long, and the CAC consisted of the digits 10 followed by the three-digit CIC. In 1998, the CIC had to be extended to four digits. Existing carriers' codes were prefixed with zero. Thus, a pre-1998 CAC of the form 10-XXX became 101-0XXX. (See the FCC's FAQ on the subject.) Since the CACs starting with 10-10 are generally the oldest and best-known ones, CACs are sometimes referred to as 10-10 codes.
Use of CACs is popular with telephone users who wish to avoid paying a regular monthly fee for access to inexpensive long-distance service. They can also be useful if encountering a "circuits busy" condition when all long distance trunks are tied up; a CAC allows selection of an alternate carrier, which may have other open long-distance trunks.
As multiple competitive long-distance carriers have been permitted in countries other than the United States, schemes similar to the CIC/CAC have spread worldwide. They are now used in (among other countries) Canada, Germany, and Japan.
Although CAC are no longer used, PIC and CIC are still common. An example of a 10-10 Dial around could be as follows. I may have AT&T as my assigned long Distance Carrier with my Local Exchange Carrier (LEC), also known as a regional Bell Operating Company (RBOC). The PIC for AT&T is 288. If there should be a public offer to have long distance calls to NY be at a special rate, the caller would dial 1010 followed by the offering telco's CIC and then the 10 digit number. This would circumvent the AT&T billing and be billed through the CIC. This allows making LD calls with different carriers without changing the assigned PIC on the account. This feature gave rise to slamming and the lesser known cramming
technique of telephone fraud.
In telephone slamming
a customer's assigned long distance carrier on their account is changed without their authorization. Some LD companies, known as switchless resellers, have contracts with LD Carriers to use their transmission lines and infrastructure. With cramming, your calls may still be going over the AT&T network (288) but some LD reseller will be billing you for the calls. Although the PIC on your account has never changed from 288, another company is billing you for LD calls going through their CIC. A LD company could tell AT&T that any calls from a particular 10 digit phone number (known as an ANI) be sent to them for billing. AT&T will pull those calls on a monthly basis and send the call tapes. It is then up to the LD Company to either bill them directly or on their local telephone bill.
, in Canada, lets customers switch to Yak Communications as their PIC (presubscribed long-distance provider), but only for outgoing calls made from Fido's Toronto calling zone. Most U.S. and Canadian wireless carriers also do not support CACs (dial-around codes) either. This is because carriers must put in a lot of effort to bill customers on behalf of IXCs (long-distance providers). Since governments do not require it, and few customers request it, most carriers have never bothered to provide CAC support.
Telecommunication
Telecommunication is the transmission of information over significant distances to communicate. In earlier times, telecommunications involved the use of visual signals, such as beacons, smoke signals, semaphore telegraphs, signal flags, and optical heliographs, or audio messages via coded...
s company, commonly called a long-distance telephone company, such as MCI
MCI Inc.
MCI, Inc. is an American telecommunications subsidiary of Verizon Communications that is headquartered in Ashburn, Virginia...
(before its absorption by Verizon
Verizon Communications
Verizon Communications Inc. is a global broadband and telecommunications company and a component of the Dow Jones Industrial Average...
), Sprint and the former AT&T
AT&T
AT&T Inc. is an American multinational telecommunications corporation headquartered in Whitacre Tower, Dallas, Texas, United States. It is the largest provider of mobile telephony and fixed telephony in the United States, and is also a provider of broadband and subscription television services...
(before its merger with SBC in 2005) in the United States. It is defined as any carrier that provides inter-LATA communication, where a LATA is a local access and transport area
Local access and transport area
Local access and transport area is a term used in U.S. telecommunications regulation. It represents a geographical area of the United States under the terms of the that precipitated the breakup of the original AT&T into the "Baby Bells" or created since that time for wireline...
.
An IXC carries traffic, usually voice traffic, between telephone exchange
Telephone exchange
In the field of telecommunications, a telephone exchange or telephone switch is a system of electronic components that connects telephone calls...
s. Telephone exchanges are usually identified in the United States by the three-digit area code (NPA) and the first three digits of the phone number (NPA-NXX). Different exchanges are generally in different geographic locations, such as separate central offices (COs, also called "wire centers").
IXCs used to carry voice traffic on analog lines
Circuit switching
Circuit switching is a methodology of implementing a telecommunications network in which two network nodes establish a dedicated communications channel through the network before the nodes may communicate. The circuit guarantees the full bandwidth of the channel and remains connected for the...
, but these days, most voice traffic is digitized. Therefore, voice traffic is more typically a data stream. These voice data streams therefore can be intermixed with data traffic, too, such as uplinks for DSL. Most commonly, links between an IXCs and COs are ATM
Asynchronous Transfer Mode
Asynchronous Transfer Mode is a standard switching technique designed to unify telecommunication and computer networks. It uses asynchronous time-division multiplexing, and it encodes data into small, fixed-sized cells. This differs from approaches such as the Internet Protocol or Ethernet that...
links carried on optical fiber
Optical fiber
An optical fiber is a flexible, transparent fiber made of a pure glass not much wider than a human hair. It functions as a waveguide, or "light pipe", to transmit light between the two ends of the fiber. The field of applied science and engineering concerned with the design and application of...
.
Carrier identification code
Each carrier (interexchange or local exchange) is assigned a four-digit identification code, the Carrier Identification Code (CIC) which was used with feature groupFeature Group
A Feature Group is United States telephone industry jargon for four types of access to long distance service. They defined switching arrangements between Local exchange carriers central offices to interexchange carriers....
s. The interexchange carrier to which calls from a subscriber line are routed by default is known as the Presubscribed Interexchange Carrier (PIC). To give telephone users the possibility of opting for a different carrier on a call-by-call basis, Carrier Access Codes (CAC) were devised. These consist of the digits 101 followed by the four-digit CIC. The CAC is dialled as a prefix immediately before dialing a long-distance phone number.
In popular usage, CACs are often referred to as "dial-around codes" (because they allow dialing around the PIC). Sometimes they are even called "PIC codes", though this term is inaccurate, since the code is being used to avoid the PIC, not to use its services.
When CICs were first introduced in 1983, they were only three digits long, and the CAC consisted of the digits 10 followed by the three-digit CIC. In 1998, the CIC had to be extended to four digits. Existing carriers' codes were prefixed with zero. Thus, a pre-1998 CAC of the form 10-XXX became 101-0XXX. (See the FCC's FAQ on the subject.) Since the CACs starting with 10-10 are generally the oldest and best-known ones, CACs are sometimes referred to as 10-10 codes.
Use of CACs is popular with telephone users who wish to avoid paying a regular monthly fee for access to inexpensive long-distance service. They can also be useful if encountering a "circuits busy" condition when all long distance trunks are tied up; a CAC allows selection of an alternate carrier, which may have other open long-distance trunks.
As multiple competitive long-distance carriers have been permitted in countries other than the United States, schemes similar to the CIC/CAC have spread worldwide. They are now used in (among other countries) Canada, Germany, and Japan.
Although CAC are no longer used, PIC and CIC are still common. An example of a 10-10 Dial around could be as follows. I may have AT&T as my assigned long Distance Carrier with my Local Exchange Carrier (LEC), also known as a regional Bell Operating Company (RBOC). The PIC for AT&T is 288. If there should be a public offer to have long distance calls to NY be at a special rate, the caller would dial 1010 followed by the offering telco's CIC and then the 10 digit number. This would circumvent the AT&T billing and be billed through the CIC. This allows making LD calls with different carriers without changing the assigned PIC on the account. This feature gave rise to slamming and the lesser known cramming
Cramming (fraud)
Cramming is a form of fraud in which small charges are added to a bill by a third party without the subscriber's consent or disclosure. These may be disguised as a tax or some other common fee, and may be several dollars or even just a few cents. The crammer's intent is that the subscriber will...
technique of telephone fraud.
In telephone slamming
Telephone slamming
Telephone slamming is an illegal telecommunications practice, in which a subscriber's telephone service is changed without their consent. Slamming became a more visible issue after the deregulation of the telecommunications industry in the mid-1980s, especially after several brutal price wars...
a customer's assigned long distance carrier on their account is changed without their authorization. Some LD companies, known as switchless resellers, have contracts with LD Carriers to use their transmission lines and infrastructure. With cramming, your calls may still be going over the AT&T network (288) but some LD reseller will be billing you for the calls. Although the PIC on your account has never changed from 288, another company is billing you for LD calls going through their CIC. A LD company could tell AT&T that any calls from a particular 10 digit phone number (known as an ANI) be sent to them for billing. AT&T will pull those calls on a monthly basis and send the call tapes. It is then up to the LD Company to either bill them directly or on their local telephone bill.
Interexchange carriers and mobile phones
Most U.S. and Canadian wireless carriers do not let their customers choose an IXC (long-distance provider). Instead, the wireless carriers send all long-distance calls through one pre-selected interexchange carrier, then bill customers directly for the calls. Fido SolutionsFido Solutions
Fido Solutions is a Canadian cellular telephone service provider currently owned by Rogers Communications. It was formerly owned by Microcell Telecommunications. Fido does, however, remain a separate entity from Rogers...
, in Canada, lets customers switch to Yak Communications as their PIC (presubscribed long-distance provider), but only for outgoing calls made from Fido's Toronto calling zone. Most U.S. and Canadian wireless carriers also do not support CACs (dial-around codes) either. This is because carriers must put in a lot of effort to bill customers on behalf of IXCs (long-distance providers). Since governments do not require it, and few customers request it, most carriers have never bothered to provide CAC support.