The Digilent I/O Explorer USB is a USB peripheral device that allows programmatic access from a personal computer to various external Input/Output (I/O) devices.
Using the Digilent Adept Software Developer’s Kit (SDK) and the Digilent Adept Runtime System
it is possible to write application programs running under either the Microsoft Windows or Linux operating systems that perform various kinds of I/O operations to devices on the I/O Explorer board itself, or through the I/O Explorer to devices external to the computer.
The I/O Explorer provides a number of I/O devices on the board itself, as well as RC servo connectors, and Digilent Pmod connectors that allow access to devices external to the I/O Explorer.
In addition to its use as a dedicated USB peripheral device, the I/O Explorer can also be used as a microcontroller development board. It features two Atmel AVR microcontrollers, one having USB device capability. Digilent makes available the firmware images needed to restore it to the factory configuration as a USB peripheral device if it has been reprogrammed with user defined firmware.
There are two UART signal pin assignment conventions in use on Digilent products. This product uses the old signal assignment convention. Connecting a product using the old convention with one using the new convention requires the use of a Digilent Pmod Crossover Cable.
for a more detailed explanation.