Silent Message (SMS0)

Silent Messages also known as "ZERO SMS" or SMS0 are messages that are not displayed on the display nor are reported to the user in any other way but trigger delivery of status reports at the time the message reaches the phone. Typically used to test phone accessibility after period of phone being switched off or out of reach.

Sending SMS0 requires setting soZeroSMS flag in Options parameter of any of SubmitMessage family of functions:


// [...]

options = (int)SubmitOptionEnum.soRequestStatusReport;
options += (int)SubmitOptionEnum.soZeroSMS;

result = clientSMPP.smppSubmitMessage("48999123456", 1, 1,
  "79123", 1, 1, "SMS0", EncodingEnum.et7BitText, "", options,
  messageID);

if(result == 0) {
  // Message submitted correctly
} else {
  // Error while submitting message
}

Message should be sent, as shown above, with et7BitText encoding and with non empty Content parameter field. The content will be ignored in the process of the delivery of the message and it is reasonable to keep it short so that the bandwidth consumed by such a messages is smaller.

SMS0 are not entirely defined

We have implemented most common way of sending ZERO SMS messages but the way in which they should be submitted in particular setup may vary depending on SMSC configuration.

In a case the above does not work you may need to contact the operator to find out what conditions should be met for the message to be treated as silent. Proper way of sending ZERO SMS can always be achieved with our libraries using other configuration mechanisms.