Legacy Wifi and MTH TIU

Buy the SER2, you can't just use a splitter cable.

Thanks for the input.  On an offshoot follow up question.  Do you need the SER2 when you are simply wiring the Legacy to the TIU.  The MTH wiring diagram shows the TIU (using an MTH serial plug) wired to an SER2 and then to the Legacy base.  here is the diagram from MTH: MTH Legacy Integration diagram.  That said, the MTH serial plug can be plugged in directly from the TIU to the command base.  The plugs fit.  I do not know if it will operate though.  Will it operate?  Then as a follow up on that.  If I am following the diagram per MTH above, and I also want to add the Lionel LCS Wifi, do I need two SER2s to add both the legacy base and the LCS wifi to be used with the DCS TIU.

Thanks again for your anticipated help.

You don't need the SER2 to wire the Legacy to the TIU.  However, I don't know if the added Legacy commands will work through the DCS without interfacing through the SER2, apparently that's where they have made some restrictions on the serial protocol. 

Where's Barry when you need him, he'd probably have a ready answer to the Legacy features.