5 pin USB HDD case special connector to the disk drive board
4 pin USB A / USB B / mini-USB jack connector to the computer
Some inexpensive portable hard-drive enclosures use a non-standard 5-pin SIL (single in-line) header — often called a Dupont-style connector — soldered directly to the HDD controller PCB in place of a standard USB socket. The connector carries the four standard USB 2.0 signals defined in the USB 2.0 Specification (USB-IF, April 2000): VBUS (+5 V), D−, D+, and GND; the fifth pin is typically no-connect. The computer-side connector is a conventional USB 2.0 Type-A or Type-B 4-pin plug governed by the same specification, which supports High-speed (480 Mbps), Full-speed (12 Mbps), and Low-speed (1.5 Mbps) transfer modes over a maximum cable length of 5 metres.
| disk drive board Name | disk drive board Pin | Direction | computer Pin | computer Name | Description |
|---|---|---|---|---|---|
| VCC | 4 | 5 | VCC | +5v Power | |
| D- | 3 | 4 | D- | Data - | |
| D+ | 2 | 3 | D+ | Data + | |
| GND | 1 | 1 | GND | Ground |
Notes
- This non-standard connector is found on cheaper USB HDD enclosures in place of a soldered USB socket.
- The housing is a 5-pin SIL (single in-line) header; the fifth pin has no electrical connection.
- The connector is typically unkeyed, so pin numbering may be reversed depending on the enclosure manufacturer. Verify polarity before connecting.
- VBUS must supply +5 V ±5 %; a USB 2.0 host port must be capable of supplying up to 500 mA for high-power devices per the USB 2.0 Specification.
Signals
- VCC — +5 V power bus supplied by the USB host; regulated to ±5 % per USB 2.0 Specification
- D− — differential data line (negative); used together with D+ for non-return-to-zero encoded USB data
- D+ — differential data line (positive); together with D− carries USB 2.0 High-speed (480 Mbps), Full-speed (12 Mbps), or Low-speed (1.5 Mbps) signalling
- GND — signal and power return ground
References
- Universal Serial Bus Specification, Revision 2.0 — USB Implementers Forum, April 2000