HushSMS is a tool to sent a class zero message (aka Flash-SMS) or a stealthy PING message to another cellphone.

The "Silent Ping" enables you to sent a SMS another cellphone without the owner getting knowledge about.

The message is discarded on the owners phone and no trace exists. You will get back a message from the operator that your message has been delivered, proving that your message has been received, and thus you can know that the owners phone is switched on.

This is not some kind of hack or whatever. It's a normal function per standard and works on any phone.

Copy the CAB file to your device and double click it.
The program is installed to Program FilesHushSMSHushSMS.exe.

There are three functions:

Send a normal SMS
Send a class zero message (Flash-SMS)
Send a stealthy message

- To send a normal sms, leave the checkboxes for "Class 0" and PING unchecked. If you want a receipt enable the "Return Confirmation" checkbox.
- To send a class zero message enable the "Class 0" checkbox and write your message.
- To send a silent PING just enable the "PING" checkbox. There is no need to write something in the Textbox, because the target phone will discard it anyway.



more info here