What is the difference between Chexit, RCM and DE5300

Chexit,  Remote Chexit Module (RCM) and DE5300  are all delayed egress options for Von Duprin.

The door opening size is the primary factor for selecting one of these options.  Other features or local code may also dictate a selection.

In summary:

Chexit
The Chexit option is a delayed egress system fully contained within a Von Duprin exit device mounted to a door.
After a Chexit exit device is pressed,  an alarm will sound and the door will remain locked for a prescribed period of time before releasing (normally 15 or 30 seconds.)
 

Remote Chexit Module (RCM)
The Chexit RCM option is for doors which are too narrow for a complete Chexit exit device.
In this case, the exit device contains the switch and blocking mechanism to keep the door closed.  However, the Chexit control board is mounted in a separate wall box next to the door.  
 

DE5300
The DE5300 is commonly used on narrow stile doors where a standard or narrow-stile Chexit is not practical.
In this case,  the Von Duprin exit device contains only a request to-exit- (RX) switch.
The Chexit control board in mounted in a separate wall box next to the door, and locking is achieved through a Schlage direct hold maglock mounted to the top of the door.

For more details, click HERE for the Von Duprin 98/99 catalog, Pages 52-56.