This Specification includes an electrical mode of operation called Fixed Rate Link (FRL), where TMDS Channels 0 to 2 are redefined as FRL Lanes 0 to 2 and the TMDS Clock channel is redefined as FRL Lane 3. Operation is defined for discrete bit rates of 3 Gbps and 6 Gbps on three lanes, and 6 Gbps, 8 Gbps, 10 Gbps, and 12 Gbps on 4 Lanes. Instead of TMDS encoding, 16b18b encoding is utilized (Section 6.5.8). FRL mode includes an electrical specification (Section6.4.1), Link Training (Section 6.4.2), and a link layer specification (Section 6.5).
In order to support FRL mode, This Specification defines a Category 3 Cable (Section 5) that includes Connector Type A,Type C, and Type D pin-compatible definitions. The Category 3 Cable also includes limits to radiated emissions. The Category 3 Cable can be used for all HDMI applications, including all features defined in H14b (e.g. HEAC).
FRL mode also includes an updated protocol with the definition of a packet structure (Section 6.5.1), block definitions (Sections 6.5.2 and 6.5.3), Reed-Solomon Error Correction (Section 6.5.4), and error-detection support (Section 6.6).
When FRL mode is enabled, This Specification also defines a Compressed Video Transport methodology using VESA DSC 1.2a (Section 7.7).