Input filtering and noise reduction

I have been busy working on my x1mill QTvcp gui but wanted to show a bit on how I handle input filtering for noise reduction. I have attached several pictures that show part of my servo enclosure for my Acra milling machine that I converted to CNC control while still maintaining all of its original manual features. The servo enclosure houses five motor drivers which are controlled by a Mesa 7I80 fpga board along with the associated interface boards.

The digital inputs from limit switches and other functions that are external to the machine all operate at 12vdc and this voltage is dropped down and filtered in the modules that are soldered to the underside of the DB15 connectors before being feed into the Mesa interface boards that provide additional input protection.

Any one doing new construction or those that are having noise related issues may wish to consider using such a filtering method. The circuit boards are all home brewed.

First of all compliment's to Johannes skills !.

I am wondering where is the noise coming from and why input filtering is necessery in your case?

At the picture i see a non-manhatten style break out board, is it a Mesa?
How would you break out this interface board if you where the designer? I am curious about your opinion.