Echolink is a computer based Amateur Radio system that allows radio amateurs to communicate with one another using Voice over IP (VoIP) technology on the internet for at least part of the path between them. It was designed by Jonathan Taylor, a radio amateur with Callsign K1RFD.

The system allows reliable worldwide connections to be made between radio amateurs, greatly enhancing Amateur Radio's communications capabilities. In essence it is the same as other VoIP applications (such as Skype), but with the unique addition of the ability to link to an amateur radio station's transceiver.

Before using the system it is necessary for a prospective user's Callsign to be validated. The Echolink system requires that each new user provide positive proof of license and identity before his or her Callsign is added to the list of validated users.

Uses

Radio amateurs using the Echolink software can operate it in one of two modes:

• Single User Mode. If they have an Internet-connected computer, they can use the computer's microphone and speakers to connect to (or through - see below) other Echolink-enabled computers over the Internet and talk to the amateur at the other end.
• Sysop Mode. This entails connecting their own VHF or UHF transceiver to their Internet-connected PC with a specially-designed hardware interface. Doing this enables another radio amateur with their own transceiver, who is within radio range of this station, to communicate with (or through) any other Echolink-equipped station anywhere in the world. This is the unique feature of Echolink.

Radio amateurs without the Echolink software or a computer connected to the Internet can take advantage of the Echolink network if they are within radio range of a sysop mode Echolink station. It is also possible to link a sysop mode Echolink station to a local repeater, further enhancing the communication possibilities