Subj : UART communications question.
To   : Ozz Nixon
From : Scott Little
Date : Sat Nov 18 2017 05:59 pm


[ On 2017-11-16 at 15:35:50, Ozz Nixon wrote to All ]

ON> My problem is, accepting the connection in the mailer, and shutting
ON> down to hand off the connection to the BBS... my old code Lowered DTR
ON> and swapped to disk and called qbbs. This is not working (may have

Add &D0 to your init string.

> &Dn - Controls data terminal ready (DTR) transition 0=Ignore DTR signal;
> 1=Return to command mode when after losing DTR; 2=Hang up, turn off auto
> answer, and return to command mode after losing DTR; 3=Reset after losing
> DTR.

IIRC you can get away with leaving DTR high in DOS but in Windows you have to
close the COM port before another program can open it which automatically
lowers DTR.  The only way around that is to pass the Win32 COM handle (instead
of the port), but that needs to be supported by your other software.


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