An interexchange carrier (IXC) is a US telecom carrier category for providers that carry calls between local calling areas, in other words long-distance carriers. The term comes from the regulatory split, after the breakup of the Bell System in the 1980s, between local exchange carriers that own the lines into homes and businesses and interexchange carriers that carry calls between local areas. The line between the two has blurred since then: many companies operate as both, and VoIP and cloud phone services usually include long distance. Buyers mostly meet the term on legacy phone bills and when cleaning up old POTS and PRI lines.
At a glance
- IXC is a US regulatory category for long-distance carriers; local service comes from a local exchange carrier (LEC).
- On legacy lines, a customer could choose a long-distance carrier separate from the local phone company.
- Long-distance carrier selection, change charges and protections against unauthorized changes still show up on some legacy bills.
- Most SIP trunking and cloud phone services bundle long distance, so a separate IXC is uncommon in modern setups.
- When replacing legacy lines, IXC accounts are easy to overlook and can keep billing.
What problem it solves
When the Bell System was broken up, long-distance and local service were separated. Local phone companies kept the lines to customers, and long distance became a competitive market served by interexchange carriers. Customers gained a choice of long-distance carrier, which helped drive down long-distance prices. The IXC category was the regulatory framework for that competition.
For today’s buyer, the useful question is different: which carriers are on our legacy lines, and what are we paying them? Older sites can have one carrier for the local line, another for long distance and sometimes another for toll-free or international calling, each on its own bill.
How it works
Local and long distance. A call within a local calling area is handled by local exchange carriers, the incumbent or a competitive carrier. A call outside the local area, on legacy service, is handed from the local carrier to the customer’s chosen IXC, which carries it across its network and hands it to the local carrier at the far end.
Carrier selection. On legacy lines, each line has a selected long-distance carrier, often called the primary interexchange carrier (PIC). Changing it can involve a charge, and a PIC freeze blocks changes without the account holder’s approval.
Access charges. Traditionally, IXCs paid local carriers access charges to start and finish long-distance calls on their networks, and some of those costs were passed to customers. In the US, FCC reforms over many years have reduced or restructured many of these charges, and details differ by service.
Taxes and fees. Long-distance and interstate services carry their own taxes and surcharges, including contributions to the Universal Service Fund in the US.
Blurring categories. Large carriers now offer local, long-distance and IP services together, and VoIP and cloud phone providers typically include long distance in their plans. The IXC label persists mainly in regulation, carrier interconnection and legacy billing.
For moving legacy voice lines to modern trunks, see our SIP trunking solution page.
When it matters for buyers
- Auditing legacy telecom bills. Look for long-distance charges, PIC charges and separate IXC accounts on older POTS and PRI lines.
- Replacing POTS lines or PRIs. Cancel or port services with every carrier on the line, not only the local carrier.
- Unexpected carrier changes. Unrecognized long-distance charges can signal slamming; a PIC freeze helps prevent it.
- Comparing voice offers. Confirm long distance is included in SIP or cloud phone pricing, and which international destinations cost extra.
Questions to ask vendors
- Which carrier is selected for long distance on each of our legacy lines, and is there a separate account or bill for it?
- Is domestic long distance included in your plan, and how are international calls priced?
- When we port numbers away from legacy lines, will the long-distance account close automatically or do we need to cancel it?
- Can you place a carrier freeze on our lines to prevent unauthorized changes?
- Which taxes and regulatory fees apply to long-distance usage on our account?
How it differs from a local exchange carrier
A local exchange carrier, whether an incumbent (ILEC) or a competitive carrier (CLEC), provides local phone service and the connection to your premises. An IXC carries calls between local calling areas. On legacy service, the two can be different companies on the same line. Today, many carriers operate in both categories, and most business buyers get local and long distance from one provider.