Apparatus and method for preventing malfunction of remote controller

An electronic device provided with a function of preventing malfunction of a remote controller, comprising:

• a remote control light reception unit for receiving a remote control signal containing a code indicating a requested operation and a counter code whose value changes each time a key of the remote controller is operated;
• a communication unit connected to a common control bus and communicating said remote control signal with other electronic devices through said control bus;
• a remote control signal acquisition unit for acquiring a remote control signal through said remote control light reception unit and said communication unit;
• and
• a remote control signal invalidation unit for, when said remote control signal acquisition unit acquires a remote control signal from said control bus, referring to the counter code contained in the remote control signal acquired from said control bus and to the counter codes contained in remote control signals previously acquired through the remote control light reception unit of the electronic device, determining whether or not these counter codes satisfy a certain condition, and carrying out processing for invalidating the remote control signal acquired from said control bus if these counter codes satisfy the certain condition;
• wherein either the value of said counter code is a count incremented by one each time the key of said remote controller is operated, and said certain condition relating to the counter codes is that the count C1 of the counter code contained in the remote control signal acquired from said control bus and the count C2 of the counter code contained in the remote control signal previously acquired through the remote control light reception unit satisfy the condition:
• C2≧C1≧C2−n (where “n” is an arbitrary positive number), or the value of said counter code is the count decremented by one each time the key of said remote controller is operated, and said certain condition relating to the counter codes is that the count C1 of the counter code contained in the remote control signal acquired from said control bus and the count C2 of the said counter code contained in the remote control signal previously acquired through the remote control light reception unit satisfy the condition:
• C2≦C1≦C2+n (where “n” is an arbitrary positive number).

A remote control transmitter for transmitting a remote control signal to a plurality of electronic devices that are connected to a common control bus and mutually communicate a remote control signal with each other, the remote control transmitter comprising:

• a counter for generating a count which changes each time a key of the remote controller is operated;
• and
• a remote control signal transmission unit for, if a key of said remote controller is operated, generating and transmitting a remote control signal containing a key code specifying the operated key and a counter code specifying the count generated by said counter;
• wherein the data length of said counter code is set such that a time period required for successively operating a key of said remote controller a number of times equal to the maximum count represented by the data length is longer than the expected maximum transmission time required for said remote control signal to be transmitted from one electronic device to another electronic device through said control bus.

A method for preventing malfunction of a remote controller used in a system in which a plurality of electronic devices are connected to a common control bus, at least one of said plurality of electronic devices is provided with a remote control light reception unit for receiving a remote control signal from a remote control transmitter, and said plurality of electronic devices mutually communicate said remote control signal with each other through said control bus, wherein:

• said remote control transmitter generates and transmits a remote control signal containing a code indicating a requested operation and a counter code whose value changes each time a key of the remote controller is operated, and
• when said electronic device acquires a remote control signal containing said counter code from said control bus, the counter code contained in said remote control signal acquired from said control bus and the counter codes contained in remote control signals previously acquired through the remote control light reception unit are referred to, it is determined whether or not these counter codes satisfy a certain condition, and processing is carried out for invalidating the remote control signal acquired from said control bus if these counter codes satisfy the certain condition;
• wherein when said electronic device acquires the remote control signal from said control bus, the counter code contained in the remote control signal acquired from said control bus and the counter codes respectively contained in “n” (where “n” is an arbitrary positive number equal to two or more) remote control signals acquired through the remote control light reception unit before the acquisition of the remote control signal acquired from said control bus are compared, and the processing for invalidating the remote control signal acquired from said control bus is carried out by determining whether or not a remote control signal containing the same counter code as the counter code contained in said remote control signal acquired from said control bus has previously been acquired through the remote control light reception unit.