🚀 go-pugleaf

I am looking for code examples (MASM or C) of how to properly raise
DTR on a COM port.  I have an application which dials the modem
after raising DTR.  The problem is that this application works fine
on most systems, but on a few systems it simply won't raise DTR all
the time.  Here is a segment of code I use to do it:

        MOV     DX, port address + offset for modem control register
        MOV     AL,0BH
        OUT     DX,AL

Should something more robust be done to properly raise DTR?   Please
reply to me directly and I'll gladly summarize here once I become an
expert on the subject. :-)
--
Tom Salzmann <tom@ramona.Cary.NC.US>