Gefen has announced a new type of high definition video extension that the company says transmits audio and video data up to 150-feet over CAT-5 cable. The US$499 HDTV Extender is available in two models that work with HD’s two most popular interfaces: DVI (digital visual interface) and HDMI (high definition multimedia interface). DVI, often the preferred format for professional a/v applications, transmits high resolution, uncompressed digital video data from source to display.