INSTALLATIONS
18 MB820 User’s Manual
J11: Digital I/O Connector (4 in, 4 out)
This 12-pin Digital I/O connector supports TTL levels and is used to
control external devices requiring ON/OFF circuitry.
Signal Name
Pin # Pin # Signal Name
IN0 1 7 +5V
IN1 2 8 OUT0
IN2 3 9 Ground
IN3 4 10 OUT1
GROUND 5 11 +12V
OUT2 6 12 OUT3
J12: System Function Connector
J12 provides connectors for system indicators that provide light
indication of the computer activities and switches to change the computer
status. J12 is a 20-pin header that provides interfaces for the following
functions.
Hard Disk Drive LED
Reset Switch
Not Defined
ATX Power On Switch
SMI / Hardware Switch
Power LED
Speaker
Speaker: Pins 1 - 4
This connector provides an interface to a speaker for audio
tone generation. An 8-ohm speaker is recommended.
Pin # Signal Name
1 Speaker out
2 No connect
3 Ground
4 +5V