50 pin IDC male connector at the controller and peripherals.
50 pin IDC female connector at the cable.
The ATA (50) Internal connector is a 50-pin IDC (Insulation-Displacement Contact) parallel storage interface used primarily with 2.5-inch hard disc drives in laptop computers and similar compact devices. It is governed by the ANSI/INCITS ATA-2 standard (document X3.279-1996), maintained by the T13 Technical Committee, which became the dominant specification for parallel ATA drives during the mid-1990s. The connector is functionally equivalent to the ATA (44) internal connector used on standard 2.5-inch drives, differing only in that a 50-pin plug is used instead of a 44-pin one. Pins 1–4 are reserved for manufacturer use and must not be connected to the host, whilst pins 5 and 6 are removed key pins that provide mechanical alignment and space for the receptacle wall.
Although there are 50 pins in the plug, the mating receptacle need contain only 44 pins (the removal of pins 5 and 6 provides room for the wall of the receptacle). The first four pins of the connector plug located on the device are not to be connected to the host, as they are reserved for manufacturer’s use. Pins 5, 6 are keys, and are removed.
| Pin | Description |
|---|---|
| 1 | Vendor specific |
| 2 | Vendor specific |
| 3 | Vendor specific |
| 4 | Vendor specific |
| 5 | keypin |
| 6 | keypin |
Notes
- Pins 7–50 carry the same signals as pins 1–44 of the standard ATA (44) connector; refer to that page for full signal assignments.
- The six-pin offset between the 50-pin and 44-pin variants means that pin 7 of this connector corresponds to pin 1 of the ATA-44 standard pinout.
- Pins 5 and 6 are physically absent (key positions); their removal ensures correct orientation of the cable and prevents damage from mis-insertion.
- Pins 1–4 are reserved for vendor-specific use by the drive manufacturer and must remain unconnected on the host side; connecting them risks damage to the drive or host controller.
- The interface carries 5 V power (no separate power connector is required, unlike 3.5-inch ATA drives), supplied through dedicated pins in the 44-pin signal region.
- This connector is a parallel ATA (PATA) interface and is electrically incompatible with Serial ATA (SATA).
Signals
- Vendor specific (pins 1–4) — reserved by the drive manufacturer; function varies by device and is not defined by the ATA-2 standard; must not be connected to the host.
- keypin (pins 5–6) — physically removed pins that serve as mechanical keys to ensure correct cable orientation and to accommodate the wall of the female receptacle.
References
- ANSI/INCITS ATA-2 (X3.279-1996), T13 Technical Committee — governing parallel ATA standard defining the 44-pin signal assignments that pins 7–50 of this connector implement (no verified deep URL available).