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Mini-ITX Mainboard Manual
JCOM1A (COM1)/JCOM1B (COM2): Serial port Connectors
The motherboard has Serial Port Connectors for connecting RS-232 Port. Only
JCOM1A supports RS-422/485.
JSEL1/JSEL2:RS-232/422/485 Switch Headers
The headers determine that JCOM1A belongs to RS-232 (Default), 422, or 485.
Note:
Please notice Pin 9 of JCOM1A and of JCOM1B. JCOM1A: +5V;
JCOM1B: Ring indicator.
14
Pin
1
Carrier detect (DCD)
2
Received data (RXD)
J C O M 1B
( C O M 2 )
3
Transmitted data (TXD)
4
Data terminal ready (DTR)
5
Signal ground (GND)
6
Data set ready (DSR)
J C O M 1 A
7
Request to send (RTS)
( C O M 1 )
8
Clear to send (CTS)
9
Ring
10
NC
JSEL2
JSEL1
RS-
RS-232
422
Assignment
TX-
TX
RX
RX-
GND
NC
NC
NC
NC
NC
JSEL1
RS-232
RS-422
RS-485
1-3
3-5
2-4
4-6
7-9
9-11
9-11
8-10
10-12
10-12
JSEL2
1-2
RS-232
3-4
RS-422
5-6
RS-485
RS-
485
TX-
TX
NC
NC
GND
NC
NC
NC
NC
NC
3-5
4-6
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