AXIOMTEK PICO300, User Manual, Page: 88 / 96

PICO300 Pico-ITX Board
82 I/O Boards (Optional)
A.18.3 COM1 and COM2 Connector (CN4)
This is a 2x10-pin connector which is compliant with AMP 2-1734507-0 for COM1 and
COM2 serial port interface. Only COM1 port has +5V level power capability on DCD and
+12V level on RI by setting JP1 (see section A.17.1). If you need COM1 port to support
RS-422 or RS-485, please refer to BIOS setting in section 4.4. The COM2 port supports
only RS-232. The pin assignments of RS-232/422/485 are listed in table below.
2 20
1 19
Pin RS-232 RS-422 RS-485
1 DCD2
2 DSR2
3 RXD2
4 RTS2
5 TXD2
6 CTS2
7 DTR2
8 RI2
9 GND GND GND
10 +V5S +V5S +V5S
11 DCD1 TX- Data-
12 DSR1 No use No use
13 RXD1 TX+ Data+
14 RTS1 No use No use
15 TXD1 RX+ No use
16 CTS1 No use No use
17 DTR1 RX- No use
18 RI1 No use No use
19 GND GND GND
20 +V5S +V5S +V5S