I missed the start of this thread but back in 1995 I designed an embedded
system (6811 based) that worked with all commercially available modems at
that time. So maybe I can help..

Assuming the modem is based on the Hayes Smartmodem (circa 1983). Then the
modem uses an internal auto-baud routine to determine the serial port speed
and parity. The auto-baud routine looks at the incoming "AT" and determines
speed and parity.

The "CONNECT" message response is usually controlled by the "S95" register.
A setting of "S95=0" should force the modem to report the actual connection
speed instead of the serial port speed. You need to watch out for the
"CONNECT" message because usually after the modem sends that response it
changes the baud of the serial line to the speed given in the message.

Paul

> > >    ATD 0123456 [enter]
> > > -> CONNECT 19200
> > >
> > >    [data] [----]
> > >    ( 1 sec pause )
> > >    +++ (Without 1 sec pause between escape codes)
> > >    ( 1 sec pause )
> > > -> OK (On-line command state)
> > >
> > >    ATH0 [CR] (Disconnect the line)
> > > -> OK
> > >
> > > How does the modem know the baud rate of the PC or PIC at
> either end? Do
> > > you have to send a dummy string so the modem can sync itself.
> >
> > The CONNECT 19200 message is telling you the carrier speed
> negotiated with
> > the other modem, this is NOT the baud rate that either modem presents to
> > its
> > serial port.
> >
> That totaly depends on the setting of one of the S registers AFAIK.  A
> common FAQ with Win95 etc, is that the dial upnetowrking box reports a
> connect speed of 115,000, which is obviously the port speed.

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