Dave, Dave, Dave,
could you please provide just a tad more hook-up detail? It's not in the book
Of course it's in the book. Page 203:
Connecting the DCS Remote Commander Receiver in Passive Mode
The DCS Remote Commander Receiver may be connected to a layout in Passive mode of operation, in the same manner as may a TIU.
Under passive mode, the DCS Remote Commander Receiver obtains its power from the tracks and a power transformer power source may not be connected to the DCS Remote Commander Receiver's Power connector. This allows the operator to control a PS2 engine using the DCS Remote Commander Receiver while, at the same time, using the layout's existing transformer controls to operate conventional engines.
For a complete understanding of Passive mode of operation, refer to Part V - Advanced Features and Functions, 10. Passive TIU Mode of Operation earlier in this book. While reviewing that section, consider the DCS Remote Commander receiver to be the equivalent of a TIU channel.
Then, read more detail, including a diagram, on page 116:
10. Passive TIU Mode of Operation
In a typical DCS layout, TIUs are connected to the layout between the transformers that provide track power and the tracks themselves. Power flows from the transformers to the tracks through the TIUs. However, some operators have determined that it is not entirely necessary to have track power flow through the TIU. Using this connection method, track power transformers and TIUs are connected to the tracks independently of each other and transformer track power does not pass through the TIU. This connection method is called Passive TIU mode.
This and a whole lot more is all in MTH’s “The DCS O Gauge Companion 2nd Edition", available for purchase as an eBook or a printed book at MTH's web store!