Q7521010: When I send a test SMS message using my GSM modem, I get the following error: 30102. What does it mean?
This means that the COM port does not exist. You only get this error if you use a COM port (like COM1) rather than a Windows Telephony device (like 'Standard 9600 bps Modem'). Error 30102 does NOT mean that the port is already in use. If the port would already be in use, you would get another error: 30103.