Question:  How many DX200 base stations can I stack together in a single location? 
Answer:  This mode of operation can be used to expand the number of users communicating through multiple DX200 Base Stations operating in the same portion of the 2.4 GHz to 2.48 GHz frequency band. Up to four DX200 base stations can be “daisy-chained” together with 3-pin XLR cables connected to the 2-wire connectors on the rear panel of each DX200 base station, following Clear-Com / RTS standards.  One base station in the chain must have the termination switch set to "ON". 
In this configuration the first base station is the "Primary" and the remaining base stations are setup as "Secondary" base stations.  Primary base stations do not require any internal dip switch changes, Secondary base stations will need an internal dip switch change to dip switch #4 position to "ON". 
Note:  To see the complete instruction for setting up multiple DX200s for Primary and Secondary operation see the attachment below.