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By SebaS
#128104
Hello everybody...

I've been years working with sim200, sim300 and sim340dz... But now I'm facing a problem.
I'm having some troubles with sim340DZ.. It was working just fine... perfectly fine... Then one day it begins to reset itself after call ready is issued...

RDY
+CFUN: 1
+CPIN: READY
Call Ready

[10 seg after]
RDY
+CFUN: 1
+CPIN: READY
Call Ready

and so on... all day... It seems it resets when trying to register to the network...

- I allready check the power supply with oscilloscope... it remains steady...

- I've read in other post that it could be a BAND issue... they were having the same problem, change band and then it work fine. I'm having 2 problems whith band...
No matter if I have the SIM card inserted or not I get this errors:

1) When trying to get band AT+CBAND? I get no reply from module... it seems like it crush... until it reset itself... If I input ANY other command module replys ok, but since I send the band command no matter what else I input from now it won't reply anything. Command is spell ok I check that.

2) When tryng to set band... I get +CME ERROR: 769 ---> Can't get control of request module...


One curious thing is that I hear a noise on the board (the same noise you hear when you put your cellphone near a speaker and you're recieving/transmitting data, the interference noise) I guess the noise is at the coil of the power supply (it's a switching type)... put some caps and now no noise...


Any help would be greatly appreciatted