How to confirm if your line is registered to avoid being among 9.2m to be barred

USSD Codes and numbers to call have been released by telecommunications companies for Nigerians to reach to confirm the status of their telephone lines.
The release of the USSD codes and numbers is coming amid the decision of the Federal Government to have the telecoms companies bar unregistered numbers from usage.
The number of lines in this category was put at 9.2 million by the Nigeria Communications Commission.
They have been categorised largely as pre-registered sims, that is sims not registered by the owners.
However, some sim owners who have been using them for several years and registered them have also received messages from their service providers to register their sims.
To check the status of your sim, the telecoms service providers have released the following details:
MTN: Dial *789*1#
Airtel: Dial *746#
9mobile: Dial 746 or 200
Glo: Text REG to 746 or 3456.