d.holmes > hardware > ATA (IDE) interface

[The details image has been removed temporarily as the jumper settings have been reported to be non-standard.]
The ATA interface more commonly known as the IDE interface appears in a number of devices other than your desktop hard drive.
Use this information at your own risk...
The ATA or IDE interface will be familiar to many computer users as the common 40 pin cable for the 3.5 inch hard disk used in most personal computers. The interface also appears in a number of other forms such as those used for the 50 pin laptop hard disk, the PCMCIA or PC-Card card as well as the Compact Flash or CF card.
From a purely physical or hardware perspective it is relatively easy to directly interface these different forms of the ATA interface. This page demonstrates connecting a 2.5" laptop ATA hard disk to a standard 40 pin IDE cable.
The drawing above shows the ATA or IDE connectors of standard 3.5" and 2.5" hard disks. The 40 pins of the standard desktop IDE cable are included in the 50 pin laptop disk interface with the same layout; they are simply offset with the remaining pins being used for power and device addressing (Master, Slave, Cable Select.) On a desktop hard disk the power and addressing connectors are separate from the 40 pin ATA bus interface.

The diagram on the right illustrates a quick and dirty method for attaching a laptop hard disk to a desktop computer. The laptop connector is the black AMP part; the blue connector would be attached to the desktop IDE cable as though it was a standard 3.5" hard disk.
The logic and motor +5V pins (41 and 42 respectively) can be connected to the same source. At the other end of the connector, the four wires connected to pins 47 through 50 are used to set the device addressing. Leave all four disconnected for SLAVE or tie 47 and 48 together for MASTER; CABLE Select is pin 48 and 50 tied together.
My home router is an industrial 386 single-board computer running FreeBSD. The disk is an old 540MB IBM ThinkPad drive connected to the computer with this 40-to-50 pin adaptor.