Other Circuits; Speaker; Jumper - IBM 5170 Technical Reference

Other Circuits
Speaker
The system unit has a 2-1/4 inch permanent-magnet speaker,
which can be driven from:
• The I/O-port output bit
• The timer/counter's clock out
• Both
Jumper
The system board has a 3-pin, Berg-strip connector. The
placement of a jumper across the pins of the connector
determines whether the system board's 2nd 256Kb of RAM is
enabled or disabled. Following are the pin assignments for the
connector.
Pin
Assignments
1 No connection
2 Ground
3 A8 (28542)
RAM Jumper Connector(J18)
The following shows how the jumper affects RAM.
Jumper Positions Function
1 and 2 Enable 2nd 256Kb of system board ram
2 and 3 Disable 2nd 256Kb of system board ram
RAM Jumper
Note: The normal mode is the enable mode. The disable
mode permits the 2nd 256Kb of RAM to reside on adapters
plugged into the I/O bus.
1-30 System Board