To learn more about the USB to TTL plug and play USB-UART adapter project checkout the promotional video below. Early bird pledges are now available for the interesting project from roughly $4 or ...

In this case a USB-TTL adapter based around the FTDI FT232R IC: the TTL-232R-3V3-AJ adapter with 12 Mbps USB on one end, and a 3 Mbps UART on the other end. [Konrad] has made the C-based code ...

The other two are TTL ports, but with an interesting twist: feed them any voltage between 1.8 V and 5 V, and they will happily work with it, which is a lot easier than messing about with TTL to RS ...