problems with siemens m20 gsm modem & c++

[Janne]

Hi,

I have one problem with siemens m20 gsm modem. It returns error when i
try to send at-command and use "\r" <return> character.

Example:
at = "ATI"+"\r";
WriteFile(hCom,at.c_str(),at.length()+1, &NumBytesWritten, NULL);
After this modem says ERROR on terminal. What return-key is supported
by m20 because "\r" return key does not work.

 

[Jacques Labuschagne]

Hi,

I have one problem with siemens m20 gsm modem. It returns error when i
try to send at-command and use "\r" <return> character.

Example:
at = "ATI"+"\r";
WriteFile(hCom,at.c_str(),at.length()+1, &NumBytesWritten, NULL);
After this modem says ERROR on terminal. What return-key is supported
by m20 because "\r" return key does not work.

How is this a C++ problem? Talk to a Siemens tech-support group.

Jacques.

 

[Karl Heinz Buchegger]

Hi,

I have one problem with siemens m20 gsm modem. It returns error when i
try to send at-command and use "\r" <return> character.

Example:
at = "ATI"+"\r";
WriteFile(hCom,at.c_str(),at.length()+1, &NumBytesWritten, NULL);
After this modem says ERROR on terminal. What return-key is supported
by m20 because "\r" return key does not work.

Generally you should ask this the guys who designed the m20.
But I would try \n

 

[Martijn Lievaart]

Hi,

I have one problem with siemens m20 gsm modem. It returns error when i
try to send at-command and use "\r" <return> character.

Example:
at = "ATI"+"\r";
WriteFile(hCom,at.c_str(),at.length()+1, &NumBytesWritten, NULL);
After this modem says ERROR on terminal. What return-key is supported
by m20 because "\r" return key does not work.

Maybe you can check the specs of the modem? You'll not get many answers in
this group, this group deals with the C++ language, not with modems.

That said, you do realize that '\r' is a seldomly used code by itself? EOL
conventions differ, but the most common are "\n" and "\n\r". '\r' may be
the code generated by the return key on some terminals, but that is about
as far as it goes, that has /nothing/ to do with how you should end you
lines, both in C++ and with modems.

<OT> IIRC hayes compatible modems (almost all of them are) use "\r\n" to
end lines. </OT>

HTH,
M4

 

[David Harmon]

at = "ATI"+"\r";

Is this supposed to mean that you are adding two (char *) pointers?

 

[Jack Klein]

Hi,

I have one problem with siemens m20 gsm modem. It returns error when i
try to send at-command and use "\r" <return> character.

Example:
at = "ATI"+"\r";
WriteFile(hCom,at.c_str(),at.length()+1, &NumBytesWritten, NULL);

^^^^^^^^^^^^^
Why are you writing one more character than the length of the C
string? Do you think the modem really wants the '\0'? Probably not.