SMS Panel
Send and receive sms with modem devices(such as USB modems)
This code has been developed with C#. You can use it to send and receive sms with modem devices(like usb modems). Just you need to add it to your project , then use it. All the methods are clear for you to read and may change if you need. If you want to use it, you do not need to know it technically. You just need to have the "phone number" and "message" string for sending a message. For receiving, you can check the received messages by the function (just call it e.g. every 1 minute).
You may have some problems(as I did) with finding and opening the COM port, but that is easy.