ATAPI 80-Pin Cable Detection

Common Options : Host & Device, Host, Device

 

Quick Review

The ATAPI 80-Pin Cable Detection BIOS feature was incorrectly named because it actually refers to the 40-pin, 80-conductor IDE cable. Despite the misleading name, the IDE cable does not have 80-pins. The 80-conductor cable only adds 40 additional ground wires to the 40 ground wires already nestled between the 40 signal wires.

The ATAPI 80-Pin Cable Detection BIOS feature controls whether both IDE controller and IDE device should be allowed to detect the type of IDE cable used.

When set to Host & Device, both the IDE controller and the IDE device will be able to detect the type of IDE cable used.

When set to Host, only the IDE controller will be able to detect the type of IDE cable used.

When set to Device, only the IDE device will be able to detect the type of IDE cable used.

The higher Ultra DMA transfer modes will only be allowed if the 80-conductor cable is used and detected by the system. Otherwise, the system defaults to slower transfer modes, even if you set the drives to use the faster transfer modes.

It is recommended that you leave this BIOS feature at the default setting of Host & Device. This ensures that the system will never incorrectly detect a 40-conductor cable as an 80-conductor cable, preventing data corruption.

 

Details

The ATAPI 80-Pin Cable Detection BIOS feature was incorrectly named because it actually refers to the 40-pin, 80-conductor IDE cable. Despite the misleading name, the IDE cable does not have 80-pins. It actually uses the same 40-pin connector as the original 40-conductor IDE cable. In fact, it is electrically and logically similar to the 40-conductor cable.

The 80-conductor cable only adds 40 additional ground wires to the 40 ground wires already nestled between the 40 signal wires. These ground wires reduce cross-talk between the signal wires and improve signal integrity. They allow the cable to reliably support transfer rates of 66 MB/s and 100 MB/s. Hence, these 80-conductor cables are essential if you want to use those higher transfer rates.

The 40-pin, 80-conductor cable was first introduced with the ATA/ATAPI-4 standard but was not mandatory until ATA/ATAPI-5 was introduced. You must use the 80-conductor cable if you intend to use the faster 66 MB/s and 100 MB/s Ultra DMA modes. Using a 40-conductor cable will force the system to revert to slower Ultra DMA modes.

Both IDE controller and IDE devices (e.g. hard disk drives, DVD writers) can detect 80-conductor cables by checking if Pin #34 of the interface is grounded. 80-conductor cables have this pin grounded while 40-conductor cables do not.

The ATAPI 80-Pin Cable Detection BIOS feature controls whether both IDE controller and IDE device should be allowed to detect the type of IDE cable used.

When set to Host & Device, both the IDE controller and the IDE device will be able to detect the type of IDE cable used.

When set to Host, only the IDE controller will be able to detect the type of IDE cable used.

When set to Device, only the IDE device will be able to detect the type of IDE cable used.

The higher Ultra DMA transfer modes will only be allowed if the 80-conductor cable is used and detected by the system. Otherwise, the system defaults to slower transfer modes, even if you set the drives to use the faster transfer modes.

It is recommended that you leave this BIOS feature at the default setting of Host & Device. This ensures that the system will never incorrectly detect a 40-conductor cable as an 80-conductor cable, preventing data corruption.

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You should only change this BIOS feature to Host or Device if the IDE controller or the IDE device cannot correctly detect the 80-conductor cable. In other words, this is a workaround for situations where the IDE controller or IDE device cannot correctly detect 80-conductor cables.

You must be sure, though, that you have 80-conductor cables installed before changing this BIOS feature to Host or Device. Both 40-conductor and 80-conductor cables are similar in length and width. They even use the same 40-pin connector.

However, 40-conductor cables are made up of 40 thicker wires, while 80-conductor cables are made up of 80 thinner wires. 80-conductor cables also have colour-coded blue, gray and black connectors.

 

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