I am trying to send an SMS using the Sim800L module and it seems to be unable to connect to the network. When I send the AT+COPS=? command it shows me a list of all the available networks along with the carrier of the sim card inserted but the module is unable to connect to the network. AT+CPIN returns an error as well. I read that changing the antenna will help but I don't think this can be the case as the networks are being detected. What could be going wrong?

  • what command you use to connect network? what error you get? what is the error with cpin command?
    – mico
    Apr 6, 2017 at 13:58
  • Are you giving it enough power? Apr 6, 2017 at 14:37
  • Yes I am, the AT commands are working and it shows me available networks as well. Actually now when I looked at the available network and the signal strength, the carrier of the sim card installed is not appearing. Only two other networks, does this mean the module is not compatible with the network of the sim installed? Can it be that the sim card is 3G?
    – Jigten
    Apr 6, 2017 at 15:25

1 Answer 1


Make sure that you are giving it enough power, seaching and registering to a network needs a current peak of 2amps, if the model you are using has a built-in regulator plug it to a stable 5v 2amp source of power and try AT+COPS? again, it should work; you can try with the computer power supply it has a 5v 2amp source.

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