The event relay device is a single-board microcontroller, operated via micropython, which interfaces between input peripherals and an event recording system.
Handheld input pads which are usable inside an MR scanner are connected to the device via a multi-channel cable, the color-coding of which is available in connector_cable.csv.
A device-type-specific micropython distribution file (e.g. .uf2 or .dfu) will need to be downloaded and flashed onto the microcontroller.