•
INTERFACE
DRIVER/RECEIVERS INSTALLED
U 10
(MAX239)
U l l
(75176)
U12
(75179)
U13
(75179)
RS-232C
in
out
out
out
RS-485 Full Duplex
out
out
in
in
RS-485 Half Duplex
out
in
out
out
956 Manual
August 1994
3.2 S E R I A L PORT DRIVER/RECEIVERS
The serial port COMA is an RS-232C port. The serial port COMB can be configured as an RS-232C
or RS-485 port. Implement your selection for this second serial port by plugging in the appropriate
driver/receiver ICs, as shown in Table 3-3.
Table 3-3. Serial Port Driver/Receiver ICs
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3 . 3 J U M P E R SETTINGS
This section describes how to set the jumpers on the SSP board.
On a 14-pin jumper group, notations such as "1/2" or "7/8" will be used to indicate that you should
install a shorting block or wire between pins 1 and 2 or between pins 7 and 8.
On a 3-pin jumper group, the jumper should always be between pins 1 and 2 ("1/2") or between pins 2
and 3 ("2/3").
On a 2-pin jumper group, the jumper will be either present or absent. The notation "short" will
indicate that you should install a jumper between pins 1 and 2, while "open" will indicate that you
should leave it out.
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3-3
