------------------------------------------------------------------------------
J1
Diskette/tape
Secondary address
Primary address
controller board
(370h)
(3F0h)
base address select
(default setting)
J2
COM1/COM2 select
Serial port set to
Serial port set to
COM1 (default
COM2
setting)
J3
Printer enabled
Parallel printer port
Parallel printer port
disabled
enabled (default
setting)
J4
Communications
Serial Port IRQ4
Serial port IRQ3
Interrupt select
selected
selected
(default setting)
------------------------------------------------------------------------------
When changing the asynchronous communications port, both the COM1/COM2 address
select (J2) and the IRQ3/IRQ4 interrupt select (J4) must be changed.
If COM 1
is selected, the interrupt IRQ4 must be selected.
If COM2 is selected, the
interrupt IRQ3 must be selected.
------------------------------------------------------------------------------
Shunt Jumper
Switch Position
Function
Switch Setting
------------------------------------------------------------------------------
J1 *
Serial communications
- open connectors = COM1
(Shunt Jumper)
on left side
IRQ4
- open connectors = COM2
on right side
IRQ3
J2 *
Controller address select
- open connectors on
(Shunt Jumper)
left = primary
controller
- open connectors on
right = secondary
controller
------------------------------------------------------------------------------
* To change the setting, remove the shunt jumper from its socket, rotate it
180 degrees, then reinstall it into the socket.
------------------------------------------------------------------------------
SW1
------------------------------------------------------------------------------
Switch 1
Fixed disk drive enabled
- ON = enabled
OFF = disabled
Switch 2
Printer port enabled
- ON = enabled
OFF = disabled
------------------------------------------------------------------------------
Switch 3 and Switch 4
Not used
==============================================================================
Chapter 8.6 Compaq Portable 286 512/2048 KByte Memory Expansion Board Jumper Settings
The total system memory for the COMPAQ PORTABLE 286 Personal Computer can be
expanded to the 1.0 to 3.0 megabyte address range by using the 512/2048 Kbyte
memory expansion board.
The base memory size depends on the type of RAM chips installed in Bank 1 of
