Vanderbilt bright blue - Installing Diode for Lock Wiring - Relay

122 bright blue Installation Manual
Installing Diode for Lock Wiring - Relay
A diode is supplied with the VRI-1 which should be fitted across 12V / 24V and COM to protect the relay contacts.
A diode is used to eliminate the voltage spike seen across an inductive load when supply voltage is suddenly
removed. This spike can damage the reader interface if not suppressed.