The rev 0.0 board incorectly labels DIN as inverted; fixed in 0.1 board.

Texas Instruments: SN74LS126ANE4
Buffers & Line Drivers Quad Bus Buffer With 3-State Outputs
http://nl.mouser.com/ProductDetail/Texas-Instruments/SN74LS126ANE4/?qs=sGAEpiMZZMutXGli8Ay4kP28D9wZ8SQIMqpIftnsrsk%3d
A pair of these are needed, so lets make a stand-alone board with two on it
Also a capacitor between Vcc (supply voltage) and GRND
see: https://github.com/OpenElectronicsLabs/level-shifter

If the controller remains separate from the ads1298 breakout board, as we have
with rev 0, LEDs for at power and possibly for each line would be nice to add.

If we wish to keep the highpass filter, we could make this path through
the board activated by a physical jumper.
