DigiOne SP won't work with NAPCO Alarm System

I’ve successfully set up a DigiOne SP on my home LAN with a fixed IP. I can get to it via my browser or successfully loopback via telnet. I’ve also gotten it to work with the serial input to a Ham radio.

However, when I connect the serial port to the output of a NAPCO alarm system the alarm system can’t connect and I get the message Communications Retry… timeout from the alarm system.

If I connect the serial output of a notebook PC to the NAPCO, I get successful communication.

When I look at the status I get CTS active. When I attempt to use the NAPCO software RTS becomes active, but I get no communication. I do notice that TCP Server is available, but TCP Client is unavailable, but I don’t know the meaning of this.

Anyone have any suggestions on what to try next?

In summary, application works great on a real serial port, and the DigiOne works great with another application!

Thanks… DHK

This should work but its hard to say what might be causing the bad communication without more info. This would be a good one to call into Tech Support about.