When YAC.NET is configured, it connects to a modem and monitors the phone line for Caller ID events. When it receives a call, and decodes the Caller ID, it then looks at a list of Listeners. These are the names and IP addresses of computers on your local network that YAC.NET will send the caller ID message to.
The list of listeners is edited by right-clicking on the YAC.NET notification icon, and choosing "Listeners...". This brings up a dialog box that contains a name, address pair for each listener. The Name is the name of the computer on the network.