Digi Connect ME RTS Line

i’d like to use the RTS line to multiplex several connection possibilities ( one of them is the Digi Connect ME ).
The ME is used as a TCP Server and the problem is, that the RTS is still low (means device can send data) although
the TCP connection was closed or never opened. It first goes high when around 4000 bytes (i suspect 4096 :wink: ) bytes
have been stuffed into the ME with no connection open. Why is that ? The device should send no more if the connection
is closed, and anyway the ME does not output any of its buffered data if the connection is (re)opened later…

So my question summarized: Is there any way to get the RTS line high always when there is no TCP connection open?!

The strange thing is that i had it running some months ago and just dont know what changed. Where can i find older firmwares ?
I also found an option “rtsflow” in the backup config file, but there is nothing in the docs about my problem or the
other serial lines (for example i observed that the DTR line is doing what i need, going low if a connection is opened,
if i could change the hardware (RTS OR DTR) would be the perfect solution… but anyway, the behaviour of these lines
is undocumented!)

Looking at the “System Information/Serial” Tab i also wonder what IFC/OFC (Input/Output flow control) are
and how to enable them, is that what im searching??

Please help me, i knew i had it working (RTS was always high when there was no connection open!)
and my software worked like a charm, was that just randomness or a hardware glitch?!?!?

Thanks in advance…