Editing Parallel ATA (section)

=== 80-conductor variant ===
[[file:Samsung HS081HA - 80 pin parallel ATA interface-9696.jpg|thumb|80 pin parallel ATA interface on a 1.8" hard disk]]
[[file:ATA cables.jpg|thumb|300px|Comparison between ATA cables: 40-conductor ribbon cable (top), and 80-conductor ribbon cable (bottom). In both cases, a 40-pin female connector is used.]]

ATA's cables have had 40 conductors for most of its history (44 conductors for the smaller form-factor version used for 2.5" drives—the extra four for power), but an 80-conductor version appeared with the introduction of the ''UDMA/66'' mode. All of the additional conductors in the new cable are [[ground (electricity)|grounds]], interleaved with the signal conductors to reduce the effects of [[capacitive coupling]] between neighboring signal conductors, reducing [[Crosstalk (electronics)|crosstalk]]. Capacitive coupling is more of a problem at higher transfer rates, and this change was necessary to enable the 66 megabytes per second (MB/s) transfer rate of ''UDMA4'' to work reliably. The faster ''UDMA5'' and ''UDMA6'' modes also require 80-conductor cables.

Though the number of conductors doubled, the number of connector pins and the pinout remain the same as 40-conductor cables, and the external appearance of the connectors is identical. Internally, the connectors are different; the connectors for the 80-conductor cable connect a larger number of ground conductors to the ground pins, while the connectors for the 40-conductor cable connect ground conductors to ground pins one-to-one. 80-conductor cables usually come with three differently colored connectors (blue, black, and gray for controller, master drive, and slave drive respectively) as opposed to uniformly colored 40-conductor cable's connectors (commonly all gray). The gray connector on 80-conductor cables has pin 28 CSEL not connected, making it the slave position for drives configured cable select.