The module is powered by USB. Operating voltage is selectable between 3.3V and 5.0V by applying a jumper across the "Power Link" header. Output pins may alternatively be configured as general purpose digital input/output and analog inputs. The module can supply up to 80 milliamps at 5.0V for external circuitry from a standard 100 milliamps USB port. Drivers are required for operation under Windows. When used on a Mac OS X or Linux based operating system, the USB-ISS will manifest as a virtual serial port (CDC). This means it will show up as COMX in Windows and in the device tree (/dev/tty....) in Mac OS X and Linux platforms.