DS option cannot be added to a Von Duprin 6000 series electric strikes in the field. It is only available factory installed.
Dual Switch monitoring (DS) option has two SPDT contacts. One monitors the tripper which is depressed when the latch bolt is inserted into the strike pocket.
The second switch monitors the condition of the solenoid, locked or unlocked. Neither switch in 6000 series electric strike monitors the deadbolt. A deadbolt monitoring has never been an option.