Have a OnePlus 2 phone with BSNL number and international roaming enabled. Once I get back to India the Outgoing SMS will not work, reason SMSC number is lost in SIM. Had been struggling to set this everytime, here is the steps that makes it work:
- Put the BSNL SIM in slot 1 (inner one)
- Dial *#*#4636#*#* from the Dialer application (This doesn’t work from any other phone application, use only the native phone application)
- This will bring up “Testing” menu
- Goto Phone information
- Scroll down, you will see SMSC with UPDATE and REFRESH buttons
- Press REFRESH, if it gives error do the following
- Enter (with the double quotes included in beginning and end) “+919440099997”
- Press UPDATE, it will not give any response back
- Press REFRESH, it should show “+919440099997”,145
- You are all set to send out SMS.
This should be same for the other OnePlus models also. Alternate way of dialing **5005*7622*+919440099997# was giving connection not available or invalid IMI code.