A hand-held electronic program playing device having a flat panel electro-optical display unit incorporated in a housing, is disclosed. Circuitry suitable for driving the display unit and manually operable controls for providing a plurality of control functions are incorporated in the housing. A replaceable...http://www.google.es/patents/US4359222?utm_source=gb-gplus-sharePatente US4359222 - Hand-held electronic game playing device with replaceable cartridges
Hand-held electronic game playing device with replaceable cartridges
