I presume that it can be used with eg. miami or similar and get full internet access,that it's not only for connecting via a termninal program?
The device, with its custom firmware, presents itself as a Hayes modem sitting on the serial port of the host computer. Insofar as a dialup modem can be used to connect to the Internet, this can be. And that would be, I suppose, PPP or SLIP dialup -- which is not very practical or what you're looking for, I think.
The goal of the creator here was to create a modem that "dials" out to the internet.