Jumper Configurations
Table A-1
Jumper Descriptions (continued).
JUMPER #
DESCRIPTION
W23-W28
(DCE †,DTE)
These jumpers allow reconfiguration of the
RS-232-C serial port 1 at J1 for DCE or
DTE. Install W23 through W28 to config-
ure the port as DCE. To configure the port
for DTE, the three jumper pairs W23-24,
W25-26, and W27-28 must be crossed over
as shown in Figure A-7. Factory default
ships serial port 1 as DCE in order to allow
communication with COM1 on the IBM
PC (see Figure A-8).
W23-W28
Function
IN †
Serial port 1 as DCE (see Figure 8)
CROSSED
Serial port 1 as DTE (see Figure 7)
W33
Install W33 to bring the 1.19318 MHz clock
to the timer 1 clock input and to J3 pin 3.
Remove W33 to disconnect this clock,
requiring an external source on J3 pin 4 to
clock the timer. This external source must be
present to prevent an open circuit on the
clock input.
Factory default installs this
jumper. The location of W33 is shown in
Figure A-9 on page A-26.
W33
Function
IN †
Timer 1 clock input is 1.19318 MHz
OUT
Timer 1 clock input is from J3 pin 4
A-22
