How to send text messages when roaming?

The domestic roaming function is turned off by default and needs to be turned on by application. The specific method is as follows.

1) opening: you can send a short message "BLMY" to 186 1 to apply for opening domestic roaming service;

2) Inquiry: You can send a short message "CXMY" to 186 1 to inquire whether the domestic roaming service has been launched;

3) Cancellation: You can send a short message "QXMY" to 186 1 to apply for cancellation of domestic roaming service;