Reference and Sources: ATA66 and ATA100 are the newest standard for IDE drives. Up until now, IDE drives have been limited in their speeds due to noise and crosstalk of the normal 40 pin cables.
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 crosstalk, 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 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.
Only remember that one should be jumpered as Master and the other as Slave. If only one drive is used, jumper it as Single (if such a mode exists, or most common Master else).
(Note that I'm numbering the wires in the cable 1,41,2,42,...39,79,40,80 so that the older IDE pin numbers still make sense.)
Internally, in all three connectors, pins 2,19,2,24,26,30,40,41-80 are connected together. This is how the shield wires get grounded.
On the blue (controller) connector, pin 34 (CBLID-) is removed. This allows detection of the ATA-66 cable. Note that this signal is also called PDIAG- and is used to communicate self-test status from slave to master.
On the gray (slave) connector, pin 28 (CSEL) is removed. This causes the drive to set itself as a slave if it is jumpered for cable select.
The black (master) connector has no pins removed. This causes the drive to set itself as a master if it is jumpered for cable select.
Please note: some controller cards and Ultra UDMA 66/100 devices cannot recognize a cable that is longer than 18". Please check your manuals.
ATA 66/100 cable (back view)
 
(40 PIN IDC FEMALE Blue to the Controller)
(40 PIN IDC FEMALE Grey to the Slave Drive)
(40 PIN IDC FEMALE Black to the Master/Single Drive)
| Controller | Slave | Master/Single | | Wire 1-80 | 1-80 | 1-80 | 1-80 |
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