A DX cluster is a network of computers, each running a software package dedicated to gathering, and disseminating, information on amateur radio DX (long-distance contact) activities.
The computers comprising the network are called nodes, the network itself being termed a cluster of nodes. The nodes may be connected either via radio links or through the internet. Internet nodes generally connect using the telnet protocol.
The system acts as an aggregator of information, accepting input from various sources, then making that data available to any user who is connected to the network.