HwB: Universal Serial Bus (USB) (Tech) Connector
Universal Serial Bus (USB) (Technical)
USB was developed by Compaq, Digital Equipment Corp, IBM PC Co., Intel, Microsoft, NEC and Northern Telecom.
Features:
- True Plug'n'Play.
- Hot plug and unplug
- Low cost
- Easy of use
- 127 physical devices
- Low cost cables and connectors
Bandwidth:
- Full speed: 12 Mbps speed (requires shielded cable)
- Low speed: 1.5 Mbps speed (non-shielded cable)
Definitions:
USB Host = The computer, only one host per USB system.
USB Device = A hub or a Function.
Power usage:
Bus-powered hubs: Draw Max 100 mA at power up
and 500 mA normally.
Self-powered hubs: Draw Max 100 mA, must supply
500 mA to each port.
Low power, bus-powered functions: Draw Max 100
mA.
High power, bus-powered functions: Self-powered
hubs: Draw Max 100 mA, must supply 500 mA to each port.
Self-powered functions: Draw Max 100 mA.
Suspended device: Max 0.5 mA
Voltage:
- Supplied voltage by a host or a powered hub ports is between 4.75 V and 5.25 V.
- Maximum voltage drop for bus-powered hubs is 0.35 V from it's host or hub to the hubs output port.
- All hubs and functions must be able to send configuration data at 4.4 V, but only low-power functions need to be working at this voltage.
- Normal operational voltage for functions is minimum 4.75 V.
Shielding:
Shield should only be connected to Ground at the host. No device should connect Shield to Ground.
Cable:
Shielded:
Data: 28 AWG twisted
Power: 28 AWG - 20 AWG non-twisted
Non-shielded:
Data: 28 AWG non-twisted
Power: 28 AWG - 20 AWG non-twisted
| Power Gauge | Max length |
|---|---|
| 28 | 0.81 m |
| 26 | 1.31 m |
| 24 | 2.08 m |
| 22 | 3.33 m |
| 20 | 5.00 m |
Cable colors:
| Pin | Name | Cable color | Description |
|---|---|---|---|
| 1 | VCC | Red | +5 VDC |
| 2 | D- | White | Data - |
| 3 | D+ | Green | Data + |
| 4 | GND | Black | Ground |
Sources: USB Specification v1.0 at USB Implementers Forum Please send any comments to Joakim Цgren.