Mac SMS Software for Multi USB Modem Screenshots
Connect your USB Modem device to the system's port via OTG cable. Select your connected device and then click on "Use Selected Device to Send SMS" option.
Select your choice from Import and Composing options to add the contacts and messages. Here, we select the "Send unique or personalized SMS to every Contact using Excel" option.
After composing the messages for every contact, now click on "Send" option to start the message sending process and wait until the process is finished.