Intel MB820 user manual J11 Digital I/O Connector 4 in, 4 out, J12 System Function Connector

INSTALLATIONS

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 Not Defined

SMI / Hardware Switch

Speaker

Reset Switch

ATX Power On Switch

Power LED

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

18 MB820 User’s Manual