# Possible Useful AT Commands

AT commands are used to configure some of the modem's operating parameters and to initiate and terminate communication. These instructions can be issued from the modem initialization string.

- M0 is used to turn off the modem speaker, M1 to turn it back on
- X0 may be used to disable busy tone detection.
- S0=r is used to set the modem to auto-answer in "r" number of rings
- Ln sets the speaker volume

Note: Any changes to the modem settings do not take effect until the next RTU or Alarmware™ session.