Controlling Operating Accessories with CAB1L Set

Click on the manual link.

https://www.lionelsupport.com/...2&productNumber=

You can use the SC-2, it receives TMCC commands directly and doesn't need a serial connection.  It'll handle six accessories or switches.

Will the SC-2 also work via serial commands sent to the base via the PC RS-233 port?  I'd like to be able to control via both the remote and PC like I can the trains.  Thanks. 

The SC-2 receives TMCC commands just like a locomotive.  It will work fine with commands that come in via the serial port on the command base.  I works fine for me using the LCS WiFi and the iPad to control switches.

so it gets connected to the U terminal of the base to receive the commands to open/close the relays?

Actually Lionel doesn't say that, but I have found out if you want it to work fast and well, connecting the com to the U terminal of the base/transformer and it works great. I use a separate transformer on the power input terminals and also connect the U terminals of the layout transformer and SC-2 transformer together. And a ground (third pin on the house wiring or pin #5 of the base db9) wire near the SC-2 is sometimes needed as well...just like a loco!