If you've ever used one of the many modem-handling libraries that exist, you're familiar with the frustration that is waiting for a response from a long-running command. Between sending your command ...

The system currently runs in text mode for readability. This would limit SMS messages to 160 characters. Warning, in alpha stages. No verificaiton of responses yet, these will be changed Arduino side ...

In the old days, a serial port often connected to an acoustic coupler that gripped a phone handset and allowed a remote connection to a far away serial port (via another phone and acoustic coupler) at ...