20
(3) COM3/COM4 (9-pin,Pitch=2.0mm): Serial Port Header
COM3:
RS232/422/485 Serial Port Header;
COM4:
RS232 Serial Port Header
6
Pin 1
COM4
*COM3
Pin NO. RS232
*RS422
(optional)
*RS485
(optional)
Pin 1
DCD
TX-
DATA-
Pin 2
RXD
TX+
DATA+
Pin 3
TXD
RX+
NC
Pin 4
DTR
RX-
NC
Pin 5
GND
GND
GND
Pin 6
DSR
NC
NC
Pin 7
RTS
NC
NC
Pin 8
CTS
NC
NC
Pin 9
RI
NC
NC
*
Note
: COM3 header can function as RS232/422/485 port header.
In normal settings COM3
functions as RS232 header. With compatible COM cable COM3 can function as RS422 or RS 485
header. User also needs to go to BIOS to set ‘
Transmission Mode Select’
for COM3 (
refer to
Page-34
) at first, before using specialized cable to connect different pins of this port.
(4) TX-RXCOM1(4-Pin,Pitch=2.0mm): RS422/485 Header
Pin1
2
3
4
TX
D
P
R
XD
P
TX
D
N
R
XD
N
TX-RXCOM1
