The data format on each type of magnetic stripe is different, for example a common bank card https://www.magtek.com/content/documentationfiles/d99800004.pdf htt

The data format on each type of magnetic stripe is different, for example a common bank card https://www.magtek.com/content/documentationfiles/d99800004.pdf https://www.magtek.com/content/documentationfiles/d99800004.... More general physics of it all: https://jacobo.tarrio.org/2014/how-magnetic-stripe-cards-work.html https://jacobo.tarrio.org/2014/how-magnetic-stripe-cards-wor... , but the specific encoding on the Metro system tickets would likely have to be reverse engineered if someone hasn't done it already I worked on a project to emulate them a long time ago :) https://hackaday.com/2009/09/23/universal-cc/ https://hackaday.com/2009/09/23/universal-cc/