Q2501b Internal GPS Mode Problem In Our Mass Production


We’ve 404 pcs Q2501b modules. One of them came with a development board and it’s used it in our development process and now we’re trying to use rest of them for mass production but there is a problem within the gps:

this is our “development module” :

Hardware Version 3.13

Production Date (W/Y): 43/2005

at+wgpsm=3  (ENTER)
+WGPSM: SW VERSION 3.0     Feb 11 2004 13:59:43 - HW VERSION 00000040

at+wgpspos (ENTER)
+WGPSPOS: 2,165441.00,201006,xxxx.0xxxN,xxx6.xxxxxE,xxx.3,2.14,0.xxx,2.33,8

( it works fine)

but with the modules that we plan to use for mass production:

at+wgpsm=3  (ENTER)
+WGPSM: SW VERSION not defined    - HW VERSION not defined

at+wgpspos (ENTER)
+WGPSPOS: -1,,,,,,,,,0   "It is not possible to define a position"

( actually we can read GPS coords from auxilary serial port but can not read the coords over GSM link)

Any idea about what is wrong with our Q2501bs ? Do we need a firmware upgrade?




It seens like the GPS is not in internal mode. Did you check that ???

The GPS also needs to be configured at Baud Rate 4800 !!!

The GPS Port at the Dev Kit is not connect to the module, it is connect to the secound GPS serial port. (the Q2501 module has some pins to directly access the GPS).



we send this sequence to the module and all of them returns “OK” from the module. I think this is enough to be sure about module is in internal mode.
Then we try to send


to the module we get

+WGPSPOS: -1,,,,,,,,,0

But one of our modules which came on a dev. board returns gps position correctly, so we think it has different firmware than the other 403 modules because it sends:

at+wgpsm=3  (ENTER) 
+WGPSM: SW VERSION 3.0     Feb 11 2004 13:59:43 - HW VERSION 00000040 

and the other modules sends:

at+wgpsm=3  (ENTER) 
+WGPSM: SW VERSION not defined    - HW VERSION not defined 



Which are the modem’s firmware version(s)? Do you want to use Open AT?
You showed us only the GPS firmware version. I think your compatibility problem comes from the modem firmware version mismatch.
You can check the modem firmware version with Ati3.

Please make sure you read the correct AT manuals which are proper for your fimware version. “New firmware little, but crucial change in some AT command”
And turn to your disributor for releasing the firmware which is on your starter kit’s modem. Or if you have not developed OAT application for that version and you can use the latest firmware, try that at first. (but read the correct at manual first :slight_smile: )

Best Regars,



+WGPSPOS: -1,0

means that the baud rate of the GPS port does not match the GSM port. Use AT+WGPSCONF=1,XXXX for this. The standard GPS rate is 4800. By the way, this is too slow if many satellites are “seen” because of the $GPGSV string.



I have the same problem. I am not intending to use OpenAT, and ati3 responds with: 650a09gg.Q2501B 1949844 122204 14:53.

AT+WGPSCONF=1,4800 or similar do not resolve problem. Also, NMEA frames are visible on main GSM UART (4800 baud). GPS is in internal mode.

Any other suggestions?


Hi. I have same problem, and try to udate to v.6.51 without success, and when i update to v.6.57 it works.

Best Regards.