When making a long distance call, many more parties are involved than in local calls, due to the nature of the call transmission.

First of all, the telephone set sends a signal to the Local Exchange Carrier's (LEC) Central Office, the CO then sends the signal to the Long Distance Carrier of the user's choice, which will in turn route the call to its destination.

Once the signal arrives at the destination location (LATA), the signal is handed off from the long distance carrier to the local telephone company serving the person that is being called.

The whole process involves different types of equipment, signaling and routing.

This section will describe the different concepts involved during a long distance call process as well as the different options when making these types of calls.