Armour v LeisureTech
IPKat - IP news and fun for everyone: On Friday 14 November, Mr Justice Arnold delivered his judgment in Armour Group Plc v Leisuretech Electronics Pty Ltd [2008] EWHC 2797 (now available from BAILII here). The case related to Leisuretech’s European patent EP1004222 (not EP1004221 as stated in the judgment) for a distributed stereo system. Leisuretech claimed that Armour were infringing their patent, and Armour in turn sought revocation of the patent on the ground that the claimed invention was obvious.
The claimed invention covered a distributed stereo audio system in which a particular type of signal cable known as ‘Cat5′ (no feline connotations) was used for both audio and power connections. In the distributed audio system (as shown in the figure, right), a cable (11) was used to connect both a signal source (5) and power supply (10) to an amplifier (4), different pairs of the cable being used for left and right audio signals and for a DC power supply from the power supply to the amplifier.
Much detail regarding the state of the art at the 1997 priority date of the patent was gone into, helped by expert witnesses from both sides. Through this, it was established that Cat5 cables were fairly commonplace in the field at the time. They were generally used for transmission of audio and control signals, but not usually for supplying DC power, largely due to the resistive losses inherent in such cables.
It was, however, well known that Cat5 cables could carry small amounts of power, and there were certain integrated circuit (IC) amplifiers widely available at the time that would at least work with these power levels. Even though these would not be regarded as ‘hi-fi’ amplifiers, Arnold J considered that relevant segments of the market did not necessarily require more than “basic hi-fi…