MSComm -- serial/modem goes off line 
Author Message
 MSComm -- serial/modem goes off line

I am using MSComm to set the modem to "automatic answer mode".
It works well until  I switch from command mode to data mode my modem goes
off line.

This is the command I use to switch from command mode to data mode,  that
causes the modem goes off line.

m_MSComm.Output = "ATO0" & ControlChars.Cr

If anyone has experienced this situation, please give a hint.

Thanks in advance,
Quynh



Sat, 09 Jul 2005 22:02:21 GMT  
 MSComm -- serial/modem goes off line
Hi,

This command tells the modem to ORIGINATE a connection.  It cannot be issued
when a modem answers.  If you wanted to do that, you would issue an ATA
command.

However... If the modem is configured to auto-answer, then if you send ANY
command while the modem is answering, the modem will disconnect.  This is
the standard mode of operation.   Auto-answer means that no command is
needed to complete the connection.

If you do not configure the modem to auto-answer, then you may issue the ATA
command while the modem is ringing.  The modem will then go offhook and
attempt to connect in answer mode.

--
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.



Sun, 10 Jul 2005 01:30:00 GMT  
 MSComm -- serial/modem goes off line

Richard,

Thank you very much for helping me out.  I understand it now.
I should not issue any other command after issuing an AT command to place
the modem in
"Auto-answer mode"  (m_MSComm.Output = "ATS0=1" & Controlchars.Cr).
Otherwise the modem  the modem will disconnect.

I have been learning a lot from you and your book.

Thanks
Quynh


Quote:
> Hi,

> This command tells the modem to ORIGINATE a connection.  It cannot be
issued
> when a modem answers.  If you wanted to do that, you would issue an ATA
> command.

> However... If the modem is configured to auto-answer, then if you send ANY
> command while the modem is answering, the modem will disconnect.  This is
> the standard mode of operation.   Auto-answer means that no command is
> needed to complete the connection.

> If you do not configure the modem to auto-answer, then you may issue the
ATA
> command while the modem is ringing.  The modem will then go offhook and
> attempt to connect in answer mode.

> --
> 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.



Sun, 10 Jul 2005 02:05:30 GMT  
 MSComm -- serial/modem goes off line

Correct me if I'm wrong, but you should be able to send "+++" to the modem
to get it into command mode from data mode.  I'm not sure if that will
cause a disconnect.

--
If you don't like lunchmeat, please remove it from my e-mail address to
send me an e-mail



Wed, 13 Jul 2005 01:27:18 GMT  
 
 [ 4 post ] 

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