The serial converter provides a 5V output rail and signal level. It is also compatible with slave devices which use 3.3V signal levels, as long as they are 5V tolerant. The device is fully powered from the USB bus. Driver support is available for Windows, Mac OS X and Linux.
Old versions of the S27 are labeled with STX and SRX. These refer to the direction of the slave device serial direction. I.e. STX is for bits going from the slave device to the USB host; SRX is for bits going from the USB host to the slave device.