IBM 220, Hardware Maintenance Manual

Page: 97 / 178

Installing options
89
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.
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 Signal
1 +5 V dc
2 -Data
3 +Data
4 Ground
Table 11. USB-port connector pin-number assignments.
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 .
6
4
2
1
3
5