Peter, at 11:12 on Feb 01 1996, you wrote to Paul Edwards...

PC> i just tried mine using Telix 3.22 DOS starting at a terminal speed of
PC> 57600, note after i change the port speed all i type is ATI4 and the
PC> modem senses the change and adjusts.

That's correct, because the serial port auto-bauds on the first AT command
(ATI4).  However, if a call comes in BEFORE you issue an ATI4 command, the
response won't be the expected RING, but garbage instead.  Seems that ATZ
is not a valid command for the port to auto-baud, which is why the usual
init string doesn't solve the problem.  If the term is configured with
AT&F1 as its init$ though, it'll work perfectly from scratch every
time.  It's a very obscure problem, but is easily and readily reproducible
here nonetheless.

PC> The modem changes speed without problem, i'd say there is something
PC> wrong with your modem.

Nope, the anomaly occurs because the USR doesn't auto-baud its serial port
on an ATZ command.  If you follow this sequence, you should be able to see
the problem quite clearly...

Start Telix with both the serial port and modem locked to 57600 bps, and
ATZ as Telix's init string.  Change your DTE to 38400 with Alt-P.  Dial 199
with your phone or modem, hang up, and wait for the modem's RING response,
which should then be just a series of unrecognisable ascii characters).

If you repeat the above with AT&F1 as Telix's init string, you'll note
that the problem no longer appears.  However, given that most people don't
continually change their serial port rates, I can't see it being a
long-term problem.

Regards, Bill

--- Msgedsq/2 3.20