IBM 770 User Manual
Keyboard/Mouse Connector
Each ThinkPad computer has a keyboard/mouse connector, where
the IBM mouse, keyboard, or numeric keypad is connected.
the IBM mouse, keyboard, or numeric keypad is connected.
Signals
The keyboard and mouse signals are driven by open-collector drivers
pulled to 5 V dc through a pull-up resistor. Figure 2-1 lists the
signals.
pulled to 5 V dc through a pull-up resistor. Figure 2-1 lists the
signals.
Figure
2-1. Keyboard and Mouse Signals
Sink current
1 mA
Maximum
High-level output voltage
5.0 V dc minus pullup
Minimum
Low-level output voltage
0.5 V dc
Maximum
High-level input voltage
2.0 V dc
Minimum
Low-level input voltage
0.8 V dc
Maximum
Connector
The keyboard/mouse connector uses a 6-pin, miniature DIN
connector.
connector.
1
2
3
4
5
6
Figure
2-2. Keyboard/Mouse Connector Pin Assignments
Pin
I/O
Signal Name
1
I/O
Mouse Data
2
I/O
Keyboard Data
3
–
Ground
4
–
+5 V dc
5
I/O
Mouse Clock
6
I/O
Keyboard Clock
Note: The maximum current for +5 V dc (pin 4) is 0.5 A for both the
mouse and the numeric keypad.
2-4 System Board