DVI Tx in Cyclone III

The Vcc terminated CML is an unique feature of the DVI physical layer. At lower rates, it can be driven from FPGA I/Os with series termination resistors. But DVI requires bit rates up to 1.65 Gbps, that can't be achieved by Altera High-Speed Differential I/O Interfaces (Stratix IV can achieve 1.6 Gbps, apart from the need for LVDS to CML level conversion). GX transmitters can easily handle the higher rates but can't provide low DVI speeds down to 250 Mbps.