This device is used for classroom roll-calls and quizes. A prototype of it made me suffer through countless chemistry lectures, but this is the production model.
The device uses a Nordic nRF24E1G. Firmware is unprotected, sitting in a 25C32 SPI EEPROM accessible through test points.
I've annotated each button with the code that it broadcasts when pressed. The GO button is used for resyncing and does not broadcast a message on the standard channel.