Often, the control circuitry is built into the motherboard, eliminating the requirement for a separate Host Adapter. There are 2 types of IDE interfaces...those for the 8-bit XT bus, and those for the 16-bit AT bus .
The cable for IDE contains 40 conductors and has no twists. Like an SCSI cable, the IDE cable uses a Dual-row Pin connector for both ends. A single cable may be used to connect two drives, or two cables may be Daisy-Chained.
Most IDE Host Adapters will support two hard drives. The first drive should be jumpered as the Master drive, and the second as the Slave drive. Plug-in IDE Host Adapters are often called Paddle-Boards, and may contain a floppy controller, and serial and parallel ports.
| Pin | Name | Dir | Description |
|---|---|---|---|
| 1 | /RESET |  | Reset |
| 2 | GND |  | Ground |
| 3 | DD7 |  | Data 7 |
| 4 | DD8 | | Data 8 |
| 5 | DD6 | | Data 6 |
| 6 | DD9 | | Data 9 |
| 7 | DD5 | | Data 5 |
| 8 | DD10 | | Data 10 |
| 9 | DD4 | | Data 4 |
| 10 | DD11 | | Data 11 |
| 11 | DD3 | | Data 3 |
| 12 | DD12 | | Data 12 |
| 13 | DD2 | | Data 2 |
| 14 | DD13 | | Data 13 |
| 15 | DD1 | | Data 1 |
| 16 | DD14 | | Data 14 |
| 17 | DD0 | | Data 0 |
| 18 | DD15 | | Data 15 |
| 19 | GND | | Ground |
| 20 | KEY | - | Key |
| 21 | n/c | - | Not connected |
| 22 | GND | | Ground |
| 23 | /IOW | | Write Strobe |
| 24 | GND | | Ground |
| 25 | /IOR | | Read Strobe |
| 26 | GND | | Ground |
| 27 | IO_CH_RDY |  | |
| 28 | ALE | | Address Latch Enable |
| 29 | n/c | - | Not connected |
| 30 | GND | | Ground |
| 31 | IRQR | | Interrupt Request |
| 32 | /IOCS16 | ? | IO ChipSelect 16 |
| 33 | DA1 | | Address 1 |
| 34 | n/c | - | Not connected |
| 35 | DA0 | | Address 0 |
| 36 | DA2 | | Address 2 |
| 37 | /IDE_CS0 | | (1F0-1F7) |
| 38 | /IDE_CS1 | | (3F6-3F7) |
| 39 | /ACTIVE | | Led driver |
| 40 | GND | | Ground |
