The analyzer trace and the event log show that sometimes there is data coming in to the serial connect from externally attached hardware when the connection is trying to be reopened but not always. I have tried this with nothing attached to the serial port also with the same issue.
The server is not closing the socket because of inactivity, in one case it had aborted it and sent a RST command because it had received malformed data and then the modem would not reconnect. We fixed this by not aborting the socket but closing it. In another instance we pushed new software for the server (the fix I just spoke about) when broke the connection and the modem would not reconnect. I have also tried setting the inactivity timer on the transport to 30 seconds, which did not help. The WR21 will still not reconnect.
If I leave the WR21 turned off for a few days it will reconnect.
Do you know how the WR21 handles an RST command?