The data sync between the BB, the SW8, and the command station can get a little wacky if they use different power sources. Try a couple different sequences of powering different things on first. The SW8 and the BB can be left on 24/7/265 with no issues. That is how I have them setup with external power on my layout. The three data lines between the BB and the sw8 are extremely sensitive to outside interference since it is a 5v low voltage connection. Twisted wires, very short wires, even some type of shielding might improve the situation. I use Cat5e /CAT6 cables with 24 AWG twisted pairs for all the low voltage (5v) data lines on my layout.
• Add Push Buttons or Toggle switches to a Switch8 Mk2
• Make Local Control Panels with NO programming.
The length of the wiring in and out of the button board will depend on the type of wire used. The more twists per foot, the longer the wire can be before noise introduced. Flat untwisted would be where the two feet rule comes in. On the other end of the spectrum you have pre twisted hookup wire that should be able to go 30 feet before causing issues.
I have attached a picture of the twisted pair cable we use for this situation.
The button board sends two bytes of data (9600,N,8,1) for each button 'event'. The first byte is the actual button data and the second byte is a complement of the first. The second byte when XORed with the first should yield 0xff allowing a modicum of error checking. The button data is as follows (in binary): 1000 nnnn = button pressed, nnnn is the button number (0-F) 0100 nnnn = button released, nnnn is the button number (0-F) Bits 4 and 5 are reserved and may represent additional button numbers in the
future so clear both bits when talking to a device that only expects up to 16 buttons.
Some devices may choose to ignore button released events.