I remember these! A quick Google yields the following, with an example of the reader mechanism http://www.telephonecardcollector.com/optical-cardphone-payphone.

I remember these! A quick Google yields the following, with an example of the reader mechanism http://www.telephonecardcollector.com/optical-cardphone-payphone.htm http://www.telephonecardcollector.com/optical-cardphone-payp... A touch of nostalgia there.