Manual
22
Serial Port Connectors
There are two serial ports supported by the board.
COM1 Connector (COM1)
The nine-pin COM1 connector consists of two connectors (RS-232 and RS-485)
attached to one logical port. Only one connector can be used at a time.
The A after the pin number in the following table indicates the lower connector (RS-
232); B indicates the upper connector (RS-485).
Pin
Signal
Pin
Signal
1A
DCD1
1B
TXD-
2A
RXD1
2B
TXD+
3A
TXD1
3B
TXD TERM -
4A
DTR1
4B
TXD TERM +
5A
GND
5B
GND
6A
DSR1
6B
RXD-
7A
RTS1
7B
RXD+
8A
CTS1
8B
RXD TERM +
9A
RI1
9B
RXD TERM -
Note
For TXD termination, a 150
Ω
, ½-watt resistor must be connected from
pin 3B to pin 4B, with pin 1B connected to pin 3B and pin 2B connected
to pin 4B.
For RXD termination, a 150
Ω
, ½-watt resistor must be connected from
pin 8B to pin 9B with pin 6B connected to pin 9B and pin 7B connected
to pin 8B.
