2

I am using SIM800 Module with Arduino Micro. It reponds well to basic AT commands. But i am unable to send SMS from this module as:

AT+CMGF=1 ERROR

Now while further debugging i saw AT+COPS? Returns 0, means not connected to any operator. That may be causing the CMGF failure. But my AT+COPS=? returns multiple operator. I have an Airtel working sim. Intialyy it was showing AIRTEL too in AT+COPS=? but not now.. anything to do with signal??

AT+COPS?

+COPS: 0

OK AT+COPS=?

+COPS: (2,"405800","405800","405800"),(1," IDEA CELLULAR Ltd","IDEA","40404"),(1,"40505","40505","40505"),,(0-4),(0-2)

What is going wrong here. any inputs?

navjosh
  • 187
  • 2
  • 2
  • 13

3 Answers3

0

It seems there's no service for your network close to you. The module is unable to register with the network. The command AT+CREG? will probably give you +CREG: 0,3 meaning it couldnt connect. AT+COPS=? is a query that yields the possible options for the result of a command or its inputs. Move your circuit to another location and see if AT+CREG? returns +CREG: 0,1 or +CREG: 0,5 which signifies a valid network registration.

SoreDakeNoKoto
  • 1,175
  • 1
  • 9
  • 16
  • my AT+GREG retruns ERROR. Now? – navjosh Oct 09 '16 at 06:15
  • OUTPUTAT OK AT+COPS? +COPS: 0 OK AT+COPS=? +COPS: (2,"405800","405800","405800"),(1," IDEA CELLULAR Ltd","IDEA","40404"),(1,"AirTel","AirTel","40410"),,(0-4),(0-2) OK AT+GREG? ERROR AT+GREG1 ERROR AT+GREG=1 ERROR – navjosh Oct 09 '16 at 06:19
  • @navjosh Compare the command in my answer and what you typed. Do they look the same? – SoreDakeNoKoto Oct 09 '16 at 12:34
  • I did AT+GREG=1 , ok , AND AT+COPS=? Returns multiple options, but AT+COPS? , error . This is the problem – navjosh Oct 11 '16 at 08:20
  • AT OK AT+CSQ +CSQ: 12,0 OK AT+CMEE=1 OK AT+COPS=? +COPS: (2,"405800","405800","405800"),(1,"40505","40505","40505"),(‌​1,"AirTel","AirTel",‌​"40410"),(1," IDEA CELLULAR Ltd","IDEA","40404"),,(0-4),(0-2) OK AT+COPS? +COPS: 0 OK AT+COPS=1 +CME ERROR: 10 AT+COPS? +COPS: 0 OK I have a IDEA sim – navjosh Oct 19 '16 at 14:57
  • My AT+CSQ changes in different location, between 12-16. I saw that 10 error is more of generic. is it something to do with power supply? or can u send me a link of a decent but cheap working gsm module that i can buy and use easily with my 3g/4g/2g sim? – navjosh Oct 19 '16 at 16:03
0

Go to an area where the signal strength is pretty good. Check for AT+CSQ, this will tell you the signal strength. Do check for AT+CMEE=1 for error report.

Nikhil Jain
  • 36
  • 1
  • Hi Nikhil, Can u tell me that these modules only work on 2g sims? not for 3g and 4g – navjosh Oct 18 '16 at 16:52
  • Hi, Sim800 is a 2G only module. Bit that doesn't mean it wont work on 3G or 4G sim cards. Consider your mobile phone as 2G (i use it, the basic models), I can use any SIM card in it given that the SIM card supports 2G also. So, there are 2 things : SIM supporting 2G and 3G or 4G and SIM800 module supporting 2G or 3G or 4G. In your case, it supports just 2G tehcnology. If your sim card has is 3G only or 4G only, you cant use it. – Nikhil Jain Oct 18 '16 at 17:30
  • Well i belive it should be 2g/3g and 4g still i always see at+cops? as 0 , but there are networks in at+cops=? . what does this suggest? – navjosh Oct 18 '16 at 17:40
  • what at+csq gives you? – Nikhil Jain Oct 18 '16 at 18:27
  • At+cops? gives 0 means the module is in automatic registration mode. Which sim card do you use? Airtel? Please check for the signal strength using at+csq. One of the reasons it is not showing the operator in at+cops =? is there is no signal available. Once the signal is available do a manual PLMN selection using AT+COPS = 1, – Nikhil Jain Oct 18 '16 at 19:26
  • Hi, thanks for ur inputs . Following are the commands output on my Terminal:AT OK AT+CSQ +CSQ: 12,0 OK AT+CMEE=1 OK AT+COPS=? +COPS: (2,"405800","405800","405800"),(1,"40505","40505","40505"),(1,"AirTel","AirTel","40410"),(1," IDEA CELLULAR Ltd","IDEA","40404"),,(0-4),(0-2) OK AT+COPS? +COPS: 0 OK AT+COPS=1 +CME ERROR: 10 AT+COPS? +COPS: 0 OK I have a IDEA sim, which is old , so i guess it is 2g only. I am usi9ng around 4V current. What u suggest now? – navjosh Oct 19 '16 at 14:55
  • CMME error 10 is for "SIM not inserted". But my sim seems ok. It fits the case . I can feel that fitting in the case and get a click sound. – navjosh Oct 19 '16 at 15:00
  • Sim not inserted, a very basic error. Usually some wiring issue inside. Where is the board mount over? some development kit? Getting a click sound doesn't confirm sim is properly inserted. Can you enable WIND indications? AT+WIND = 255. After you enable wind indication, insert the sim card and restart the module and see if you get some +WIND indications or not. Problem doesn't seems to be network side as sim is not getting detected so it wont connect to any network. Try with some other sim which can be detected or check the wiring of the board or the sim rack. – Nikhil Jain Oct 20 '16 at 16:26
  • Hi, I using Arduino uno+SIM800L . Connections are simple tx,rx,vcc(4.0V),gnd and reset. I tried using AT+WIND = 255 , IT RETURNED ME CME:100 error. do u suspect my module to be corrupted? can u tell me any simple cheat module that will work for me. i wann make msg+call. If u can provide a link, that will be great :D – navjosh Oct 23 '16 at 14:31
  • Go with Telit [link](http://www.telit.com/cellular/) or sierrawireless [link](https://www.sierrawireless.com/products-and-solutions/embedded-solutions/) I personally prefer sierra modules. – Nikhil Jain Oct 23 '16 at 15:57
  • 1
    I think you should better check the RF PIN and antenna before opting another module as your module is working fine and responding to AT commands. The only issue is with the network. Check the hardware guide , is the RF properly set up or not – Nikhil Jain Oct 23 '16 at 16:04
0

Might be some power issues, but I fixed mine by just trying some AT command

AT+CBAND?

Then, AT+CBAND="DCS_MODE"

That works for me. Give it a try man.

Myrman de Luna
  • 1
  • 2