flexfax: Sending to a line shared between voice and fax

[Ronald Greenberg <rig@math.luc.edu>]

Is it supposed to be possible with my FlexFAX (circa 1994) or a more up
to date HylaFAX to send faxes to a line that is shared between voice and
fax?
The line has an answering machine on it that says to leave a message at
the tone or to proceed with a fax now.  Presumably, when it hears my fax
machine,
it is supposed to switch the call to the receiving fax machine. 
Presumably, if a person answers instead of the answering machine, they
also have
a way to switch the call to the receiving fax.  I've succesfully sent to
this line before by putting paper into an ordinary fax machine, but when
I send something via sendfax, I get a response of "No carrier
detected".  Can I change the outcome by altering the line in
/usr/spool/fax/etc/config.cua0
that says

ModemDialCmd:                DT%s@           # T for tone dialing, @ for
silence

or by adding some codes to the phone number used in the sendfax
command?  Please CC me on any responses to the mailing list, because I
don't ordinarily
read it (but I've searched diligently in the FAQ on the web).
-- 

Ronald I. Greenberg	(Ron)		rig@math.luc.edu