Re: How to pass Extra AT Commands to RASDial before dialing ??


as Valter already noticed, the switch of the DTR line doesn't reset the
modem. It is used as a hangup sequence. A modem that is online will detect
the change of DTR and drop the line. After that, it can accept AT commando's
on it's serial line. (GPRS modem's don't have a line anymore, but the
principe remains)

The problems usually are the AT commando's in the registry that are sent to
the modem during a rasdial sequence. One of them is the ATZ command which
causes the modem reset. (As far as I remember) Change this setting in the
registry to a simple AT and you can hapilly send your modem initialise
commands before your rasdial, directly to the comport.

You might even implement the DTR trick, to make sure that your modem is
ready to accept AT commands.

The registry key should be HKLM\Drivers\Unimodem\Settings. There you will
find the reset sequence.

hope this helps,


"Massimo B." <MassimoB@xxxxxxxxxxxxxxxxxxxxxxxxx> wrote in message
Hi all,
we use under WinCE 4.2 a GPRS modem connected via USB and using COM
driver from FTDI, our problem is that we need to pass AT commands before
RASDial makes the call.
This because before RASDial makes the connection it sets the DTR and reset
our modem to the power on state and we lose any setting that we make via
direct write to COM port.
(for your understanding the RASDial set DTR also when it disconnects)

If is possible to pass any extra AT commands via RASDial will be great but
if someone of you know how to disable the use of DTR in RASDial it is much

Waiting for your opinions
Thanks to all

Massimo B. (Italy)
R & D department