[1] http://en.wikipedia.org/wiki/Low-pass_filter
[2] http://en.wikipedia.org/wiki/Multi-Point_Interface
[3] http://www.kepware.com/support/manuals/siemens-s7-mpi-manual.pdf
[4] http://au.rs-online.com/web/p/touch-screen-hmi-displays/0563958/
[5] http://www.electronics-tutorials.ws/filter/filter_2.html