Method and Apparatus for Use in an Access Control System

Claim 2

A decoder microchip suitable for use in an electronic remote control apparatus operating in accordance with the principle of code stepping, characterized in that it comprises: - means for performing a decoding function on a received transmission value and an identification number embedded in the decoder microchip, so as to generate from the transmission value, a decoded unit number and a decoded counter value; - means for comparing the decoded counter value with a decoder counter value range; and - means, upon a valid synchronization command having been decoded by the decoder microchip, for synchronizing the decoder counter value with the counter value of an encoder microchip which has generated the synchronization command.

Claim 3

A decoder microchip as claimed in claim 2, characterized in that it comprises means for performing a format scan on 10 signals so as to identify and respond to valid transmission values.

Claim 4

A decoder microchip as claimed in claim 2, characterized in that it comprises distinguisher means for distinguishing between a decoded unit number for normal operation and a synchronization command.

Claim 5

A remote control system operating in accordance with the principle of code stepping, characterized in that it comprises a transmitter remote control device and a receiver remote control device, the transmitter remote control device comprising an encoder microchip, the encoder microchip comprising: - means for performing a non-linear encoding function on an identification number embedded in the said microchip and a combination of the unit number and stepping counter value, so as to generate a transmission value which is decodable by a related decoding function; and - means for generating, upon a synchronization command being given thereto, a counter value which is encodable together with the synchronization command, to generate a synchronization transmission value which will facilitate the synchronization of a decoded microchip having the same identification number, the receiver remote control device comprising a decoder microchip comprising: - means for performing a decoding function on the received transmission value and an identification number embedded in the decoder microchip, so as to generate from the transmission value a decoded unit number and a decoded counter value; - means for comparing the decoded counter value with the decoder counter value range; and - means, upon a synchronization command having been entered into the decoder microchip, for synchronizing the decoder counter value with a counter value of a encoder microchip.

Claim 6

A combined encoder and decoder microchip for use in a remote control system operating in accordance with the principle of code stepping, characterized in that it comprises: - means for performing a non-linear encoding function on an identification number embedded in the said microchip and a combination of a unit number and a stepping counter value, so as to generate a transmission value which is only decodable by a related decoding function having access to the same identification number; - means for generating, upon a synchronization command being given thereto, a counter value which is encodable together with the synchronization command, to generate a synchronization transmission value which will facilitate the synchronization of a related decoder microchip having the same identification number; - means for performing a decoding function on a received transmission value and an identification number embedded in the microchip, so as to generate from the transmission value, a decoded unit number and a decoded counter value; - means for comparing the decoded counter value with the decoded counter value range; and - means, upon a valid synchronization command having been decoded by the microchip, for synchronizing the decoder counter value with the counter value of an encoder microchip which has generated the synchronization command.

Claim 7

A transmitter remote control device operating in accordance with the known principle of code stepping, comprising encoder means and transmission means adapted to transmit a transmission value receivable by a receiver remote control device capable of responding thereto, characterized in that the encoder means comprises means for performing an encoding function on an identification number embedded in the encoder means and a combination of a unit number and a variable counter value so as to generate a transmission value incorporated in the transmission, and in that the transmission value is decodable through a related decoding function performed by the receiver remote control device.

Claim 8

A receiver remote control device operating in accordance with the known principle of code stepping, comprising decoder means, characterized in that the decoder means comprises means for performing a decoding function on a combination of a transmission value and an identification number, so as to generate a decoded unit number and a decoded counter value; and means for comparing the decoded counter value with a counter value range.

Claim 9

A receiver remote control device as claimed in claim 8, characterized in that it comprises means for providing an output indicative of a valid transmission value it has received.

Claim 10

A receiver remote control device as claimed in claim 8, characterized in that it comprises means for comparing the decoded counter value with a decoder counter value range, wherein the decoder counter value range was obtained from a uni-directional synchronization process pre-performed on the receiver remote control device by a transmitter remote control device.