The relay box is used to switch high current loads for the igniter and the release for the slide mount. It also provides the UMBILICAL output to trigger loads on board the rocket if desired but it is not high current capable. The relay box provides the RAIL SWITCH signal to feed the lift off detect signal back to the Camera Controller. The relay box requires a battery to provide current to power its outputs.
The circuit board has all the components mounted directly to it and it in turn is fastened to the lid of the enclosure. The Relay Box uses Anderson Connectors for the outputs and the battery connection. Typically the Relay Box is secured to the base of the Launch Pad for easy access for igniter cables, slide mount release clips, and the lift off activation switch.