The ultra ATA has 80 wire conductors and 40 pins, the extra wires help make the new ATA66 and ATA100 hard drives perform like SCSI drives (reduces cross-talk, improves signal integrity). All pins straight from 1 to 1, 2 to 2 and so on. Line 34 on the cable should be notched or cut (this may be difficult to see). It is used between one ATA66/100 PCI controller card and up to two storage devices.
To support UDMA66/100/133 hard drives, ATA66/100 cable should be installed by connecting the BLUE connector onto the motherboard, BLACK connector to the Master hard drive and GREY connector to the Slave hard drive.