EchoLink (echolink.org) 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. Echolink allows repeaters to connect to each other, as well as individuals to connect directly or to other repeaters. For example a Ham using a HT handled can connect through a local repeater to another repeater located anywhere in the world and talk to another Ham. In essence, this would allow a ham in Louisville using their walke-talkie to talk to another Ham in Japan who is also using their walkie-talkie each communicating via radio to their local VHF repeater which are then linked via Echolink across the world.
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.
EchoLink software allows licensed Amateur Radio stations to communicate with one another over the Internet, using streaming-audio technology. The program allows worldwide connections to be made between stations, or from computer to station, greatly enhancing Amateur Radio's communications capabilities. There are more than 200,000 validated users worldwide — in 162 of the world's 193 nations — with about 5,000 online at any given time.
The ARTS Club W4CN Repeater supports Echolink (Node#425970), and using the software any amateur can connect to the repeater via the internet and Echolink and talk via the repeater radio connection to other radio users. See the W4CN Repeater Echolink page for more info.