This video demonstrates a 16-Channel relay board with a USB interface module installed.  By default, ProXR controllers automatically refresh relays.  When automatic relay refreshing is turned off, the relays will not change state when relay control commands are sent.  Instead, only the relay memory will change.  A separate relay refreshing command must be sent to make the controller update the status of the physical relays.  This allows users to send many relay control commands to the controller in any order, then refresh all relays simultaneously.