The USB to Serial project is a break-out board for the CP2103 from Silicon Labs.
I was looking for an inexpensive Serial Port solution for my Mac, that I could build into my projects without external adapters. I have the KeySpan USA-19HS, which works very well, but it is too expensive to build into projects and you must use a level shifter to safely use TTL or 3.3 volt signals.
For projects where adapters are not convenient you can use the CP2103. With this break-out board, you have pins for all of the RS-232 signals, four GPIO pins and 5 volts, 3.3 volts and ground. I made it with the intention of testing designs on a bread-board, but it may also be incorporated into another design by simply plugging it in like a DIP.
If you would like to make your own, you can download the PCB EPS from the Downloads page. I would suggest taking a look at the PCB Notes page on my How Tos page. To solder the CP2103 in this project I used a Hot Air Re-work station from SparkFun, and for the rest of the parts I used my regular soldering station.
