Data Cable Pinouts
CableWholesale.com has a nice archive of technical articles about cables, connectors, how to choose and use them, etc.
This page describes data cable connectors and their pinouts. See the audio-video cable page for descriptions and pinouts for HDMI cables. Jump to a cable type:
What shall we call these devices....
In the beginning, or at least around 1986, was Western Digital's Integrated Drive Electronics (IDE) interface. That defined the low-level connection from a computer system board to a disk storage device. IDE refers to the disk controller being integrated into the drive and IDE providing an interface to a computer bus, initially the ISA bus. The host computer sees the storage device as an array of 512-byte blocks with a simple suite of interface commands.
That led to AT Attachment and AT Attachment Packet Interface standards, so ATA/ATAPI is a complicated but accurate designation.
In 1994 Western Digital introduced Enhanced IDE (EIDE) or ATA-2 drives.
Roughly 2007-2009 Serial ATA or SATA largely replaced ATA/ATAPI technology on motherboards, leading to ATA being renamed PATA for Parallel ATA. SATA uses the same command set as PATA, but it uses high-speed serial cables moving data at 1.5, 3.0, and 6.0 Gbps.
DD0 - DD15 — Data line 0 through 15.
IOCHRDY — I/O channel ready.
CS — Cable Select.
With the arrival of the Ultra DMA/33 mode, the cable went from 40-conductor to 80-conductor ribbon cable. The added 40 conductors are all ground lines, reducing crosstalk of the higher speed signals from what would have been adjacent conductors on 40-conductor cables.
|RST||DD7||DD6||DD5||DD4||DD3||DD2||DD1||DD0||GND||DDRQ||I/O W||I/O R||IOCHRDY||DDACK||IRQ||ADDR 1||ADDR 0||Chip select 1P||Activity|
|GND||DD8||DD9||DD10||DD11||DD12||DD13||DD14||DD15||VCC in||GND||GND||GND||CS||GND||N/C||DMA66 detect||ADDR 2||Chip select 3P||GND|
Pin 20 is usually not there, it may be a blank spot on the plug and missing a pin on the drive or motherboard connector to force plugging it in correctly oriented. But some flash drives use it to supply VCC to the drive.
Pin 28 is connected at the motherboard and master drive (far end) connectors, but not at the slave drive (middle) connector.
Pin 34 is connected normally (that is, to conductor #34) at the motherboard and slave drive connectors, but connected to ground within the motherboard connector.
|Standard||Other names||Transfer modes (MB/sec)||Standardized|
PIO 0, 1, 2
(3.3, 5.2, 8.3 MB/sec)
Single-word DMA 0, 1, 2
(2.1, 4.2, 8.3 MB/sec)
Multi-word DMA 0
|ATA-2||Fast ATA, Ultra ATA, EIDE, Fast IDE||
PIO 3, 4
(11.1, 16.6 MB/sec)
Multi-word DMA 1, 2
(13.3, 16.7 MB/sec
Like ATA-2 but without
single-word DMA modes
|ATA/ATAPI-4||ATA-4, Ultra ATA/33, UDMA/33||
Ultra DMA 0, 1, 2
(16.7, 25.0, 33.3 MB/sec)
|ATA/ATAPI-5||ATA-5, Ultra ATA/66, UDMA/66||
Ultra DMA 3, 4
(44.4, 66.7 MB/sec)
|ATA/ATAPI-6||ATA-6, Ultra ATA/100, UDMA/100||
Ultra DMA 5
|ATA/ATAPI-7||ATA-7, Ultra ATA/133, UDMA/133||
Ultra DMA 6
PATA disks will have their data and power connectors on opposite ends. In between will be a set of jumper pins in which you can set the device to be the master or slave, or explicitly set it for "cable select", or leave off the jumper and allow it to use cable detection.
Cable select is the right choice for modern hardware. It may be marked as "CS" in a small diagram included on the label on the device case.
Now, as for how to set the jumper, refer to the documentation for your disk. There is no general rule. Ask Google the manufacturer name and model number to find out how to set the jumper.
As you see from this stack of three disks, the number of available jumper pins varies. The disk at top has six jumper pins, the one at middle has eight, and the one at bottom has ten.
The contact areas on the pins are small, so multiple pins are ganged together for ground and the various voltages.
|Function||3.3 V||Ground||5 V||Ground||Staggered spinup||Ground||12 V|
Used for smaller devices, such as notebook drives.
|Function||Device present||5 V||Diagostic||Ground|
Used for 1.8-inch drives with SATA 2.6.
|Function||3.3 V||Ground||5 V||reserved||vendor specific|
|Function||Ground||A+ (Transmit)||A- (Transmit)||Ground||B- (Receive)||B+ (Receive)||Ground||coding notch|
First-generation SATA, now called SATA 1.5 Gbit/s, moves data at 1.5 Gbit/second. The data encoding overhead reduces the actual throughput to 1.2 Gbit/s.
SATA 3 Gbit/s doubles the data transfer rate and adds command queueing.
The final SATA 6 Gbit/s specification was released in 2009. However, mechanical drives can barely saturate a SATA 3 Gbit/s link, so there will be little market for SATA 6 Gbit/s until drive I/O speed increases significantly.
These are laid out here as viewed looking into the plug:
|Micro-B USB 3.0 Pinout|
|2||USB 2.0 differential pair D-|
|3||USB 2.0 differential pair D+|
|4||USB OTG ID for identifying lines|
|6||USB 3.0 signal transmission line (-)|
|7||USB 3.0 signal transmission line (+)|
|9||USB 3.0 signal receiving line (-)|
|10||USB 3.0 signal receiving line (+)|
|USB 1.x/2.0 Mini/Micro Pinout|
|1||+5 V power|
Yes, these are terribly archaic, but to be complete....
|N/C||N/C||Index||Motor enable drive 0||Drive select 1||Drive select 0||Motor enable drive 1||Direct select||Head step||Write data||Floppy write enable||0=Track 00||0=Write protect||Read data||0=Head select||1=Disk change 0=Ready|
Lines 9-16 are reversed
|N/C||N/C||Index||Motor enable drive 1||Drive select 0||Drive select 1||Motor enable drive 0||Direct select||Head step||Write data||Floppy write enable||0=Track 00||0=Write protect||Read data||0=Head select||1=Disk change 0=Ready|