A new class of consumer digital cables known as Compact Active Cables has arrived in the market. Compact Active cables embed signal processing technology directly into the cable structure to improve bandwidth performance and extend the capability of many communications standards such as HDMI, USB, DisplayPort and Infiniband. In Compact Active cable solutions the embedded chip compensates for the data loss which occurs when very high speed signals are transmitted over copper. This active boosting means that active cables can be made thinner, longer, faster, lighter and more compact than their passive equivalents. Using HDMI as an example case, in this paper the limitations of HDMI passive cables are reviewed and the principles of Compact Active cable technology are explained.