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[LTE] AT+CNUM command causing registration failure on LTE devices #1627

merged 1 commit into from Dec 7, 2018


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commented Dec 7, 2018


AT+CNUM command is used in the registration process just to log the phone number of the inserted SIM. It has been observed that some SIMs in LTE devices have invalid characters in the phone number string that causes this command to error.

40.796 AT send       9 "AT+CNUM\r\n"
40.826 AT read ERR  49 "\r\n+CME ERROR: invalid characters in dial string\r\n"

This prevents the registration process from completing and the device will blink green continuously.


Remove the AT+CNUM command.

Steps to Test

Test on a unit that was previously causing this error. It should now connect without a problem.


  • User is totes amazing for contributing!
  • Contributor has signed CLA (Info here)
  • Problem and Solution clearly stated
  • Run unit/integration/application tests on device
  • (N/A) documentation
  • Added to after merging (add links to docs and issues)
removes AT+CNUM command
- When the AT+CNUM command errors, it will prevent the registration process from completing.
- It is also not used for any reason other than logging the phone number of the inserted SIM.

@technobly technobly added the bug label Dec 7, 2018

@technobly technobly requested a review from sergeuz Dec 7, 2018

sergeuz approved these changes Dec 7, 2018

@sergeuz sergeuz merged commit 8ce5367 into develop Dec 7, 2018

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@sergeuz sergeuz deleted the fix/atcnum branch Dec 7, 2018

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