I have a Probotix relay in a RTR system, four axis.  How do I configure the system to activate a router. Signal out, and what else.

Think you are asking how to set it up so the relay switches the router on?
If thats it then Config menu then Ports and Pins, OutPuts then set the port and pin number, that your relay is connected to, to one of the outputs. Once you have done that then go to spindle setup page (Still in Ports and Pins) and take the tick out the Disable Spindle relay box and enter the number of the output you just set up into the two boxes for M3 and M4.

Hood

thanks Hood, I'll try it........................