not receive CONNECT string

[Morello Tommaso]

I wrote a C# application to send AT command to my modem with serial
port. Comunication is ok, but when the modem is connect with remote
terminal (eg. fax, telephone, etc.) I don't receive the string
"CONNECT xxxxxxx". I don't have problem with others status (BUSY, NO
CARRIER, ETC.).

How can I see if modem is connect?

I tried send AT command with Windows HyperTerminal too. With it, I
received the string "CONNECT xxxxxxxx", but this don't happenes with
my C# application.
Use HyperTerminal special set?
Is it serial port problem?

Someone can help me?

 

[Dmitriy Lapshin [C# / .NET MVP]]

Hi Morello,

HyperTerminal most likely sends a so called initialization string to the
modem. This string, actually a sequence of AT-commands, tells the modem to
use certain connection speeds, protocols and, in particular, configures the
messages output by the modem to the COM port.

So you need to find out which AT command is responsible for configuring the
presence of the "CONNECT" command and ensure the appropriate command is sent
by your application prior to any attempt to establish a dial-up connection
to a remote system.

 

[Dick Grier]

Hi,

You have to do two things. First, initialize the modem to output responses
(this is not automatic). Make sure that you send the command: ATE0V1Q0X4
to the modem before dialing.

Then, after dialing, you must wait for the modem response. You can enter a
loop, or use some event notification method, as is appropriate for whatever
serial class you are using.

--
Richard Grier (Microsoft Visual Basic MVP)

See www.hardandsoftware.net for contact information.

Author of Visual Basic Programmer's Guide to Serial Communications, 3rd
Edition ISBN 1-890422-27-4 (391 pages) published February 2002.