NetDXCluster provides amateur (ham) radio operators access to AR DX Cluster nodes using telnet via the Internet. An Internet connection is required. This software only works under Mac OS X 10.1.3 or later It also requires the BSD subsystem that is typically installed when installing OSX. If the BSD subsystem option was not installed, you will probably receive a quick failure on starting it up. NetDXCluster works by launching Telnet in a shell and letting that do the networking.