Service manual

C-30 Sun Ultra 2 Series Service Manual • July 1996
FIGURE C-7 Selected Jumper Settings
The jumper description includes a brief overview of serial port jumpers, flash PROM
jumpers, and additional motherboard jumpers and connector blocks.
Jumpers are identified on the motherboard by J designations. The following figure
distinguishes jumpers with identifying asterisks. Jumper pins are located
immediately adjacent to the J designator. Pin 1 is marked with an asterisk in any of
the positions shown by the following figure. Ensure that the serial port jumpers are
set correctly.
FIGURE C-8 Identifying Jumper Pins
C.5.1 Serial Port Jumpers
Serial port jumpers J2104 and J2105 can be set to either RS-423 or RS-232 serial
interface. The jumpers are preset for RS-423. RS-232 is required for digital
telecommunication within the European Community. The following table identifies
serial port jumper settings. If the system is being connected to a public X.25 network,
the serial port mode jumper setting may need to change from RS-423 to RS-232
mode.
To change the serial port mode jumper setting:
Closed
Open
2-3
1
1-2
1
Pins
Part number
J 2 X X X
*
*
*
*
*
*