Intel LGA775 MB865 - Manual (Page 21)

INSTALLATIONS
CN2, J1, J10, J13: Serial Ports
CN2 (COM1) is a DB-9 connector, while J1 (COM2), J10 (COM3) and
J13 (COM4) are pin headers.
COM1 COM2/COM3/COM4
Signal Name Pin # Pin # Signal Name
DCD, Data carrier detect 1 6 DSR, Data set ready
RXD, Receive data 2 7 RTS, Request to send
TXD, Transmit data 3 8 CTS, Clear to send
DTR, Data terminal ready 4 9 RI, Ring indicator
GND, ground 5 10 Not Used
J1 (COM2) is jumper selectable for RS-232, RS-422 and RS-485.
Pin # Signal Name
RS-232 R2-422 RS-485
1 DCD TX- DATA-
2 RX TX+ DATA+
3 TX RX+ NC
4 DTR RX-
NC
5 Ground Ground Ground
6 DSR RTS-
NC
7 RTS RTS+ NC
8 CTS CTS+ NC
9 RI CTS- NC
10 NC NC NC
MB865 User’s Manual 17