http://philtechnicalblog.blogspot.co.uk/2005/04/for-mid-90s-vintage-monitor-sony-pvm.html

http://philtechnicalblog.blogspot.co.uk/2011/05/tricaster-tally-light-interface-for.html

http://www.phaedrusltd.com/pages/html/netiom-xap.html

http://www.arduino.cc/

http://www.raspberrypi.org/faqs

http://blog.makezine.com/2011/08/16/enough-already-the-arduino-solution-to-overexposed-celebs/

http://radiomagonline.com/tutorials_tips/engineers_notebook/passive_attenuators/