USB cables and hubs
You need a 4-pin cable to connect devices to USB 1 or USB 2. If you plan to attach more than two USB devices, you must use a hub to connect the devices. The hub provides multiple connectors for attaching additional external USB devices.
USB technology provides up to 12 megabits-per-second (Mbps) speed with a maximum of 127 external devices and a maximum signal distance of five meters (16 ft) per segment.
USB-port connectors
Each USB port has an external connector on the system board for attaching USB- compatible devices.
The following table shows the pin-number assignments for the USB-port connectors on the system board.
Pin | Signal |
| |
1 | +5 V dc |
| |
2 | -Data |
| |
3 | +Data |
| |
4 | Ground |
| |
Table 11. USB-port connector pin-number assignments.
Keyboard port
There is one keyboard port on the system board.
Note: If you attach a standard (non-USB) keyboard to the keyboard connector, the USB ports and devices will be disabled during the power-on self-test (POST).
The following table shows the pin-number assignments for the keyboard connector on the system board.
Pin | I/O | Signal |
| | |
1 | I/O | Data |
| | |
2 | N/A | Reserved |
| | |
3 | N/A | Ground |
| | |
4 | N/A | +5 V dc |
| | |
5 | I/O | Clock |
| | |
6 | N/A | Reserved |
| | |
Table 12. Keyboard connector pin-number assignments .
Installing options 89
