Antitheft apparatus for automotive vehicle and method of registering ID No. therein

Claim 1

An antitheft apparatus for an automotive vehicle, comprising: a transponder provided in an ignition key, for storing an ID number of its own ignition key therein; a transmit/receive unit provided in an ignition key cylinder, for transmitting a transmit signal to said transponder to receive the ID number, and for receiving a signal of the ID number of the ignition key inserted into the ignition key cylinder; and an immobilizer unit for, in antitheft mode, collating the received ID number of the ignition key with ID numbers already stored therein and outputting an engine start enable signal when the received ID number matches one of the stored ID numbers but an engine start disable signal when it does not match and for, in ID number register mode, registering the received ID number therein; said immobilizer unit further comprising means for releasing the ID number register mode; wherein with said immobilizer unit remaining in the ID number register mode after registration of the received ID number, said means releases the ID number register mode into the antitheft mode automatically when the received ID number of the ignition key inserted into the ignition key cylinder is received again and thereby twice successively by said transmit/receive unit.

Claim 5

A method of registering an ID number of an ignition key in an antitheft apparatus, comprising the steps of: checking whether a first ignition key is inserted into an ignition key cylinder and further rotated to an IGN ON position; if the first ignition key is inserted into the ignition key cylinder and further rotated to the IGN ON position, transmitting a transmit signal to a transponder of the first ignition key inserted into the ignition key cylinder to receive a first ID number of the first ignition key; registering the received first ID number in a memory as the first ID number; checking whether a second ignition key is set to the IGN ON position; if the second ignition key is set to the IGN ON position, transmitting the transmit signal to a second transponder of the second ignition key inserted into the ignition key cylinder to receive a second ID number of the second ignition key; checking whether the received second ID number is the same as the first ID number; if the received second ID number is the same as the first ID number, releasing an ID number registered mode; if the received second ID number is not the same as the first ID number, storing the second ID number in the memory as the second ID number; checking whether a maximum number of ID numbers have been registered; if the maximum number of ID numbers have not been registered, repeating the ID number register processing; and if the maximum number of ID numbers have been registered, releasing the ID number register mode.

Claim 6

A method of registering an ID number of an ignition key in an antitheft apparatus, comprising the steps of: checking whether a first ignition key is inserted into an ignition key cylinder and further rotated to an IGN ON position; if the first ignition key is inserted into the ignition key cylinder and further rotated to the IGN ON position, transmitting a transmit signal to a transponder of the first ignition key inserted into the ignition key cylinder to receive a first ID number of the first ignition key; registering the received first ID number in a memory as the first ID number; checking whether a second ignition key is set to the IGN ON position; if the second ignition key is set to the IGN ON position, transmitting the transmit signal to a second transponder of the second ignition key inserted into the ignition key cylinder to receive a second ID number of the second ignition key; checking whether the received second ID number is the same as the first ID number; if the received second ID number is the same as the first ID number, releasing an ID number registered mode; if the received second ID number is not the same as the first ID number, storing the second ID number in the memory as the second ID number; checking whether a maximum number of ID numbers have been registered; if the maximum number of ID numbers have not been registered, repeating the ID number register processing; and if the maximum number of ID numbers have been registered, releasing the ID number register mode.

Claim 7

A method of registering an ID number of an ignition key in an antitheft apparatus, comprising the steps of: checking whether a first ignition key is inserted into an ignition key cylinder and further rotated to an IGN ON position; if the first ignition key is inserted into the ignition key cylinder and further rotated to the IGN ON position, transmitting a transmit signal to a transponder of the first ignition key inserted into the ignition key cylinder to receive a first ID number of the first ignition key; registering the received first ID number in a memory as the first ID number; checking whether a second ignition key is set to the IGN ON position; if the second ignition key is set to the IGN ON position, transmitting the transmit signal to a second transponder of the second ignition key inserted into the ignition key cylinder to receive a second ID number of the second ignition key; checking whether the received second ID number is the same as one of ID numbers already stored; if the received second ID number is the same as one of ID numbers already stored, releasing an ID number register mode; if the received second ID number is not the same as any of ID numbers already stored, storing the second ID number in the memory as the second ID number; checking whether maximum ID numbers have been registered; if the maximum ID numbers have not been registered, repeating the ID number register processing; and if the maximum ID numbers have been registered, releasing the ID number register mode.

Claim 8

A method of registering an ID number of an ignition key in an antitheft apparatus, comprising the steps of: checking whether a first ignition key is inserted into an ignition key cylinder and further rotated to an IGN ON position; if the first ignition key is inserted into the ignition key cylinder and further rotated to the IGN ON position, transmitting a transmit signal to a transponder of the first ignition key inserted into the ignition key cylinder to receive a first ID number of the first ignition key; registering the received first ID number in a memory as the first ID number; checking whether a second ignition key is set to the IGN ON position; if the second ignition key is set to the IGN ON position, transmitting the transmit signal to a second transponder of the second ignition key inserted into the ignition key cylinder to receive a second ID number of the second ignition key; checking whether the received second ID number is the same as one of ID numbers already stored; if the received second ID number is the same as one of ID numbers already stored, releasing an ID number register mode; if the received second ID number is not the same as any of ID numbers already stored, storing the second ID number in the memory as the second ID number; checking whether maximum ID numbers have been registered; if the maximum ID numbers have not been registered, repeating the ID number register processing; and if the maximum ID numbers have been registered, releasing the ID number register mode.

Claim 22

A method of operating an antitheft system for an automotive vehicle having an ignition switch and an engine comprising the steps of: receiving a coded signal representing a key security code corresponding to a vehicle ignition key; and with the system remaining in a registration mode after storing said key security code, automatically switching from the registration mode, for storing said key security code as a registered security code responsive to receipt of said coded signal, to an antitheft mode, for issuing a start signal to enable starting of the vehicle engine responsive to receipt of said coded signal if said coded signal corresponds to said registered security code, responsive to said coded signal being received again and thereby twice in succession.

Claim 23

A method of operating an antitheft system for an automotive vehicle having an ignition switch and an engine comprising the steps of: receiving a coded signal representing a key security code corresponding to a vehicle ignition key; and with the system remaining in a registration mode after storing said key security code, automatically switching from the registration mode, for storing said key security code as a registered security code responsive to receipt of said coded signal, to an antitheft mode, for issuing a start signal to enable starting of the vehicle engine responsive to receipt of said coded signal if said coded signal corresponds to said registered security code, responsive to said coded signal being received again and thereby twice in succession.

Claim 27

A method of operating an antitheft system for an automotive vehicle having an ignition switch and an engine comprising the steps of: receiving a coded signal representing a key security code corresponding to a vehicle ignition key; and automatically switching from a registration mode, for storing said key security code as a registered security code responsive to receipt of said coded signal, to an antitheft mode, for issuing a start signal to enable starting of the vehicle engine responsive to receipt of said coded signal and said coded signal corresponding to said registered security code, if said key security code has been previously stored as one of a plurality of registered security codes.

Claim 28

A method of operating an antitheft system for an automotive vehicle having an ignition switch and an engine comprising the steps of: receiving a coded signal representing a key security code corresponding to a vehicle ignition key; and automatically switching from a registration mode, for storing said key security code as a registered security code responsive to receipt of said coded signal, to an antitheft mode, for issuing a start signal to enable starting of the vehicle engine responsive to receipt of said coded signal and said coded signal corresponding to said registered security code, if said key security code has been previously stored as one of a plurality of registered security codes.

Claim 29

A method of operating an antitheft system for an automotive vehicle having an ignition switch and an engine comprising the steps of: storing a number of registered security codes up to a maximum number of registered security codes; receiving a coded signal representing a key security code corresponding to a vehicle ignition key; and automatically switching from a registration mode, for storing said key security code as one of said number of registered security codes, responsive to receipt of said coded signal, to an antitheft mode, for issuing a start signal to enable starting of the vehicle engine responsive to receipt of said coded signal and said coded signal corresponding to one of said number of registered security codes, if a count of said number of registered security codes stored thereby equals said maximum number of registered security codes which can be stored.

Claim 30

A method of operating an antitheft system for an automotive vehicle having an ignition switch and an engine comprising the steps of: storing a number of registered security codes up to a maximum number of registered security codes; receiving a coded signal representing a key security code corresponding to a vehicle ignition key; and automatically switching from a registration mode, for storing said key security code as one of said number of registered security codes, responsive to receipt of said coded signal, to an antitheft mode, for issuing a start signal to enable starting of the vehicle engine responsive to receipt of said coded signal and said coded signal corresponding to one of said number of registered security codes, if a count of said number of registered security codes stored thereby equals said maximum number of registered security codes which can be stored.