JoeG,
1st when you purchase your new DCS unit make sure it's a Rev L then have both the old and new Hand Held Remotes and TIU updated with the latest changes. I made the mistake of not matching everything one time and had a run away train on the 2nd level in the Conventional mode, not a pretty sight. Barry advised me that I needed all my DCS components upgraded to the latest level, before using both my Hand Held remote controls to control my full layout.
Now for the upgrading of the Hand Held Remote Controls to fully rechargeable, Willygee (Billy Ingram) here on the OGR forum is the man to see for this fantastic engineering upgrade. He does the full upgrade and instructs on how to use it. You will need different rechargeable Batteries for both remote control units and the new 6VDC Battery Tender, Bill has engineered a quick coupling/battery set up, for the hand held DCS Remote Control, with wire combo to keep one remote control on the charger while using the other, then simply switch, when the one gets low from usage, works like a dream. I never have to worry about the hand held remote having bad or low batteries now. If needed you an even use the remote control while it's on the charger, if you only own one, hand held remote control. I love this upgrade, MTH needs to incorporate this rechargeable engineering, into their DCS package as an option. Bills's fully rechargeable upgrade for the DCS, actually works better than the Legacy 990 recharge station. I use the DCS Hand Held Remote Control (HHRC) about 80% of the time and the Legacy Cab2 about 20 %, of the time, the Cab 2 controls all my FasTrack wireless Command Control Switches, which the DCS HHRC can not due. IMO DCS & Legacy operate best when run together.
PCRR/Dave