Ensure a connection still exists

If the communication status ever changes from the normal state, the system uses default controls to ensure that a connection still exists.

The default controls are:

• +++

• ATHO

Refer to Modem command requirements for descriptions of the commands. If the modem is disconnected successfully, it is placed back into an available state. If the modem cannot be disconnected successfully, it is placed into an out-of-service state.