USB-UART-Opto
If you often work with devices which require TTL UART interface, it is highly recommended to use some kind of isolation to protect your PC and we have just the solution for you.
USB-UART-Opto integrates into one single small device the functions of a USB to UART bridge and an opto-isolator without the need of an additional power supply. It is based on prolific PL2303HX, has an on-board DC-DC converter and a pair of 6n137 optocouplers, enabling it to work at speeds of up to 6 Mbps. Its provides a 5V TXD signal, but works with both 5V and 3V levels on the RXD signal making it compatible with tons of devices.
The provided isolation gives you the comfort that your precious laptop won't be destroyed because of a stupid wiring mistake or a power surge.
Due to the popularity of the chipset drivers are available for most operating systems. You can find them on Prolific web site .