Vehicle anti-theft protection as transponder and key and readable identification memory

摘要

Transponder and key are so electrically or mechanically connected as to render the transponder unusable when it is removed from the key. The transponder can be mechanically destroyed and is joined to the key via an ideal break point, preferably formed by notches on the transponder housing as inserted in the key. Transponder and key are joined by an electrical connection. In detail, the notches etc break up the transponder on removal from the key. The electrical connection if used is broken directly the transponder is withdrawn, possibly supplemented by a resistance built into the key head and essential to transponder function. Otherwise the connection can take the form of a data transmission coil which once broken eliminates any command transmission.