ATA Cable Explained
The ATA cable is used to connect storage devices like hard drives and floppy drives. I will explain how they are working with your drives.
By reading through the entire page you will learn how they are attached to your drives, which standard you should use according to your drives and what is supported by cables made of 40 and 80 wires and more.
Composition
Each ATA ribbon cable has a flexible plastic ribbon that contains the wires where there is 2 or 3 connectors that are fixed to it. 1 connector to each extremity and 1 connector close to the master connector if it is a cable with 3 connectors.
Note the red line on the image; all ATA cables have a red mark pin 1. This mark is made to help the user to figure out which side to plug the connector on the drive or the motherboard.
You should be able to find 18 inches and 36 inches cables in computer stores. The 18 inches is mostly the only one used and the 36 inches are more used for special reasons.
Computer Ribbon Cable Also Called IDE Cable
The Ribbon, 40 And 80 Wires
At the beginning all ribbon cables were being made of 40 wires and were supporting a certain range of standards. Nowadays, there are cables of 80 wires and they are supporting higher standards.
Note for both, only connectors with 40 pins are used.
The cables with 80 wires are made of 40 grounds that are interleaved with the other 40 wires. This way all previous 40 wires are grounded.
To help you understand the differences between the 40 and 80 wires, take a look at the table below. See the different standards supported by both of them.
Cable Used |
Standard |
Name |
Transfer Mode |
40 wires |
ATA-1 |
ATA |
DMA |
40 wires |
ATA-2 |
Ultra-ATA |
DMA |
40 wires |
ATA-3 |
Ultra-ATA |
DMA |
40 wires |
ATA-4 |
Ultra-ATA/33 |
Ultra-DMA/33 |
80 wires |
ATA-5 |
Ultra-ATA/66 |
Ultra-DMA/66 |
80 wires |
ATA-6 |
Ultra-ATA/100 |
Ultra-DMA/100 |
80 wires |
ATA-7 |
Ultra-ATA/133 |
Ultra-DMA/133 |
The Connectors, Master And Slave
Ribbon cables are made of 1 or 2 connectors for drives. With 1 connector, only a drive sets to master can be attached to the cable. But with 2 connectors, 1 drive must be set to master and the other set to slave. You can also use a cable with 2 connectors to plug only 1 drive, in that case you have to set the drive to master and use the master connector only, otherwise it will not work at all.
A question lots of people ask me is what will happen if I use a cable with 40 wires on a drive with a standard supported only by a cable with 80 wires?
In such case, it will still work, but the cable will not be able to offer the performance wanted. If your drive supports Ultra-DMA/66, then the cable with 40 wires will use the highest mode it can support. In that case Ultra-ATA/33 and your drive will run at Ultra-DMA/33 instead of Ultra-DMA/66.
[I hope you appreciated the ATA cable guide
and I invite you to take a look at the other guides.]
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