Antitheft system using keyboard of radio receiver - is for entering numeric code which disables antitheft measures when correct code is used

摘要

The antitheft system has the keyboard belonging to a radio receiver connected to a coder when a special switch is operated. A numeric code can then be entered via the keyboard and if found to be correct disables the antitheft system. The radio receiver may be controlled by a microprocessor which may also be used by the antitheft system. The ignition circuit of the vehicle remains open until the correct code is entered at the keyboard. When the correct code has been entered the ignition can be closed via the keyboard. A timing circuit ensures that the code must be entered within a given time.