Front panel connectors (CN1,CN2,CN3,CN4)
You may want to install external switches to monitor and control the
Speaker connector (CN1)
The
HDD LED connector (CN2)
The LED indicator for hard disk access is an active low signal (24 mA sink rate).
Reset switch (CN3)
If you install a reset switch, it should be an open single pole switch. Momentarily pressing the switch will activate a reset. The switch should be rated for 10 mA, 5 V.
Power LED/keyboard lock connector (CN4)
You can connect an LED to indicate if the CPU card is powered on. Pin 1 of CN4 supplies power to the LED, and pin 3 is the ground.
You can use a switch (or a lock) to disable the keyboard. In this state, the PC will not respond to any input from the keyboard. This is useful if you don’t want anyone to change or stop a running program. Simply connect the switch between pin 4 and pin 5 of CN4.
If you need to make your own cable, you can find the pin assign- ments for the board’s connector in Appendix B.
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