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Hi:)
I've problem with SIM900 module.
Seems to me that it's not able to maintain a connection.

What i know this firmware is supporting europe (i come from Poland).
SIM has no PIN code and it's properly working on smartphone.
Firmware version:
SIMCOM_Ltd
SIMCOM_SIM900B
Revision:1137B09SIM900B32_ST


Response for "AT" Command:
OK


It's detecting an operator:
AT+COPS?

+COPS: 0,0,"Orange PL"


But signal quality is 0:
AT+CSQ

+CSQ: 0,0

OK


Led status:
https://www.youtube.com/watch?v=AY6JEwgJMM0&feature=share

Any tips what can be wrong?

What I have tried:

I've tried changing firmware on SIM900. Any results.
Posted
Comments
MateoGlowinski 2-Aug-18 3:09am
   
I'm powering it from laboratory power supply which is set to 5V DC and current limitation set to 2A.
Richard MacCutchan 2-Aug-18 3:25am
   
I think you need to post this in a hardware forum. QA is for programming issues.
MateoGlowinski 2-Aug-18 3:27am
   
Right, i will do that:)
Jochen Arndt 2-Aug-18 3:40am
   
Check your antenna connection (socket, plug, cable, and antenna).
MateoGlowinski 2-Aug-18 4:01am
   
hm... everything seems stable. I tried with two different antennas (smaller and bigger one)
Jochen Arndt 2-Aug-18 5:08am
   
If you want to reply to a comment use the "Reply" button right of the comment like I have done here. Then the initial poster will get an email notification.

I saw this only by chance when coming back from your post at Hardware & Devices to post this:
Please don't crosspost (ask the same at multiple places on one site). You might get answers on both from different people who did not saw your other post. As a result you might get the same or a similar answers on different threads. That is wasting time of people trying to help you.

I suggest to delete your post at Hardware & Devices because you got replies here meanwhile.

Back to your problem:
It is - as already said - very probably a hardware problem for which this site is not the best choice.

If you tried it with two antennas, they are probably OK. But did you checked the connector and it's soldering on the PCB? A quick web research shows that multiple users of the SIM900 had problems due to badly soldered antenna sockets. A "+CSQ: 0,0" is an indicator for such hardware connection problems when other non connection related commands are working.
MateoGlowinski 2-Aug-18 17:18pm
   
But according to https://www.multitech.com/support/resolutionid/5033860 "CSQ 0,0" means that signal is fine, isn't it? Command "AT+CREG?" is returning "+CREG: 0,2" which is saying that SIM is not registred.
Jochen Arndt 2-Aug-18 18:01pm
   
CSQ 0,0 means that the signal strength is at the lowest level (-113 dBm or less).

From your link: "Ideally signal should be between 10-31"

A value of 10 corresponds to -93 dBm which is 100 times stronger than -113 dBm!

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