All desktop ATA cables have three 40-pin connectors, one that connects to the ATA interface and two that connect to ATA/ATAPI drives. All standards-compliant ATA cables—there are many that do not comply—share the following characteristics:
An ATA cable must be at least 10 inches (0.254m) long, and no longer than 18 inches (0.457m).
The center-to-center distance between one end connector and the middle connector must be 5 inches (0.127m) minimum to 12 inches (0.304m) maximum. The distance between the center connector and the other end connector must be 5 inches minimum to 6 inches (0.152m) maximum.
Pin 1 is indicated by a colored stripe on the cable (usually a red stripe on a gray cable).
ATA cables are keyed, either by blocking Pin 20, by using a keyed shroud, or both.
ATA cables come in three varieties:
A standard ATA cable uses a 40-wire ribbon cable and 40-pin connectors in all three positions. All 40 conductors connect to all three connectors. The only real variation, other than cable quality, is the positioning of the three connectors. A standard ATA cable requires using Master/Slave jumpering for connected devices. All connectors on a standard ATA cable are interchangeable, which is to say that any drive may be connected to any position, and the interface itself may be connected to any position, including the center connector. A standard ATA cable may be used with any ATA/ATAPI device through ATA-33. If a standard ATA cable is used to connect ATA-66/100 devices, ...