TMDS stands for Transition Minimized Differential Signaling. It was developed by Silicon Image as part of the Digital Display Working Group and can transmit heavy data through a cable. It is used with the Digital Video Interface (DVI) and the High-definition Multimedia Interface (HDMI).
In an HDMI cable there are three separate TMDS channels, each are capable of transfer rates up to 3.4Gbps giving a total 10.2Gbps. HDMI 1.3 doubled the previous clock speed of 165Mhz to 340Mhz. This brought the available bandwidth from 4.95Gbps to 10.2Gbps. Each channel carries data from one video component (Red, Green, Blue, for example) at up to 48-bit resolution along with control data and digital audio.