If these are both simplex nodes and you are running app_rpt version 2.10, try adding rxondelay=25 in /etc/asterisk/usbradio.conf on both nodes. Be sure to restart asterisk on both machines after making this change. The other problem is most likely Internet related. Steve WA6ZFT -> thanks for the reply Steve. This is version 0.208 - perhaps in my version this parameter has no effect? It seemed not to do anything. Would it be worth getting the update installed? To clarify - these are two nodes in the same computer. They are both configured as DUPLEX as they are intended to control two repeaters (someday). What I am intending to test is the linking of the two repeaters together. I get the pingpong effect even if I connect in the monitor-only mode. And it doesn't matter if I connect node 2 to node 1, or do it the other way around. Ken KE2N