Ring Alerts

Get alerts on new messages with Ring Alerts

When a new message enters the MT queue, the gateway sends out a ring alert at the last known location of your RockBLOCK. This free service notifies your device of the queued message so that you can initiate an Extended SBD Session to download it.


Ring Alerts are turned OFF in RockBLOCK's default configuration

Enable Ring Alerts using the command AT+SBDMTA=1

Check the status of Ring Alerts using the command AT+SBDMTA?

Any changes to this setting need to be saved. This can be done using the command AT&w0
If changes are not saved this setting will revert to its default when the device powered off

If you are not receiving Ring Alerts check that:

  • You have enabled Ring Alerts using the +SBDMTA=1 command
  • The device is powered on
  • The device or external antenna has a clear view of the sky

An SBDRING announcement is issued if the RockBLOCK interface is in command mode, or when it next returns to command mode.

When a ring alert is received, you can use the +SBDIXA command which retrieves the MT message following a ring alert. If a +SBDIXA is not transmitted by your RockBLOCK within 20 seconds of this first ring alert, the gateway sends a second one. If there is still no response, the Ring Alerts are cancelled, and you will not receive a third.

The +CRISX command may be used to query the RockBLOCK as to the reason for the most recent assertion of the RI signal.

/* Check modem communication */


/* Receive response */


/* Turn off Flow Control */


/* Receive response */


/* Execute Ring Indicator Status command */


/* Receive Response */

+CRIS: <tri>,<sri>,<timestamp>

/* Initiate an Extended SBD Session */


/* Receive response */

+SBDIXA: <MO status>, <MOMSN>, <MT status>, <MTMSN>, <MT length>, <MT queued>\r

/* See SBDIXA Key for information on each parameter */



- indicates the telephony ring indication status:
0 No telephony ring alert received.
1 Incoming voice call.
2 Incoming data call.
3 Incoming fax call.

- indicates the SBD ring indication status
0 No SBD ring alert received.
1 SBD ring alert received.

- Iridium System Time stamp of the most recent Ring Alert.



The SBDIXA command denotes the status of your sent, received and queued messages following a Ring Alert. It is exactly the same as a standard SBDIX command with the exception that, if used between ring alerts, it disables the second ring alert:

- Any returned number with a value of 0 to 2 indicates your message has been successfully transmitted. Any number above 2 indicates that the message has not been successfully transmitted.

- This number denotes the MO message number and cycles between 0 and 65535.

0 - No messages waiting to be received. 1 - New message successfully received. 2 - Error during mailbox check / message reception.

- This number denotes the MT message number and cycles between 0 and 65535.

- The size (in bytes) of the MT message.

- The number of MT messages in the queue waiting to be downloaded.

AT commands in this chapter