Cassettes of recording tape are provided with an electronic memory including semi-conductor circuits mounted in the cassette housing for storing data relating to the cassette or tape therein. A memory error signal device is also provided in the cassette housing having states representing that data stored...http://www.google.ca/patents/US4338644?utm_source=gb-gplus-sharePatent US4338644 - Magnetic tape cassettes provided with memory circuits for storing information
