Unstable AT-command replies from GSM-radio

[McFlown]

I'm programming on a program that uses cell broadcast messages to determine your position. (http://gknavigation.de) - It was a project at "youth research" this year.
It is based on an idea of W.Back...

Now I want to get rid of a external gsm phone at the position determination, because the new Pocket PC Phone Edition have a integrated radio functionality.

I've written a small terminal-prog. for the XDA (http://gknavigation.de/beta.htm), which let's you sent modem-command into the gsm and recieve replies.

On the XDA2 it is working well until the line "AT command interpreter ready" is displayed on the terminal. After that common AT-commands like "AT+CBC" won't work any longer, and result with an "ERROR". :cry:

The line (and the errors as result) seems to apear after a few seconds the port is open.

I think I have opened the port and initialized the shared use of the gsm serial communication well. :?

Check out that Sourcecode please:

The .DLL-file-project, which is written in C++ and opens/closes the port:
http://mcflown.net/eVC/XDAcom_func/
The visual basic project, which is for reading and writing operations, and user interface:
http://mcflown.net/eVB/XDAterm/

Greeting and sorry for the hopfully not thaaat bad englisch! :oops:

F. Wetzel[/url]

[McFlown]

Hasn't really nobody any suggestions?
:?
Florian

[McFlown]

Hi,

Just wanted to let you know that I will have alook and see what I can do
for you.

Have you got a break down of what you are trying to achieve

A summ ups are written in German, sorry!
But i will try to describe it briefly:

My prog recieves the messages of the cell broadcast channel 221 by a mobile
phone connected via any inteface. (Bluetooth, IrDA, RS-232)
In Germany this channel contents data about the position and sending
direction of the mobile (fix installed) stations. With some (or many) tricks
i'm able to determinate your own own position up to a 50 meters. (in best
case - depending on the number of installed stations)
This is drawn on a map.

The prog is running under PPC and PC, but the PC version is less
interesting, because the PPC is more portable.

Newerdays, the PPCs have a integrated GSM radio module, so that it should be
possible to recieve those CB-messages vie the internal modem.
By that the users of XDA/MDA/... in Germany would get an alternative to GPS
for navigation/orientation without buying new hardware!

Lateron this prog is perhaps compatible with Tomtom. - I'm checking how to
do it!

Greeting, and thanks in advance!

Florian

[nutitija]

Hey man i must say i respect you , you have done great work !!!

I am currently working on xda2 as university project and i need to access internal modem of xda ... so might need ur help ... i would wanna help u too and i probly will ... just letting u know i'll try a bit on ur prob and get back to ya ...

any advice ou can give me to access the internal modem ??

great job ! talk soon

[pai]

On the XDA2 it is working well until the line "AT command interpreter ready" is displayed on the terminal. After that common AT-commands like "AT+CBC" won't work any longer, and result with an "ERROR". Crying or Very sad

The line (and the errors as result) seems to apear after a few seconds the port is open.

I think I have opened the port and initialized the shared use of the gsm serial communication well. Confused

Check out that Sourcecode please:

after read your source, i think:

- set Sleep time between each other AT commands > 100ms for response time of GSM modem
- try to close the com port and re-open it before sending another AT-command.
- try to use only RIL port or COM2, don't open them and use them at the same time.

[nutitija]

hey i read through the code its good but i dont see how u get "AT Interpreter Ready" in the VB app ... i looked hard !!! can anyone enlighten me ??

[shamus]

I guess "AT Interpreter Ready" is the answer from device.

[mamaich]

AT Interpreter Ready is sent by device after radio resets itself. You should never see this reply.

[nutitija]

ok - when i get "AT interpreter Ready" from my terminal it allows me to send an AT commands, so in a way i'm guessing that i should get it -

Indeed it happens when the GSM resets does anyone have more explanations on how it appears ???

[pai]

i get "AT interpreter Ready", too.

[ionsphere]

Could someone compile the DLL and EXE and post them here in one zip? Would save me having to install Visual Studio !