The 500-200KS is an Auxilliary Relay for use on fire alarm systems.  This unit is designed for use on a 24V sounder circuit and can be used to provide an output signal to a variety of services on activation of the fire alarm system.  It also has an inbuilt adjustable timer which can delay the operation of the relay after a fire alarm activation.  An example of where this may be used could be an autodialler connection.  This would allow the user to investigate the alarm activation before the autodialler is activated.