User`s manual

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.

RS-232

RS-

422

RS-

485

Assignment

1 Carrier detect (DCD) TX- TX-

2 Received data (RXD) TX TX

3 Transmitted data (TXD) RX NC

4 Data terminal ready (DTR) RX- NC

5 Signal ground (GND) GND GND

6 Data set ready (DSR) NC NC

7 Request to send (RTS) NC NC

8 Clear to send (CTS) NC NC

9 Ring NC NC

JCOM1 A

(COM1)

JCOM1B

(COM2)

10 NC NC NC

JSEL1/JSEL2:RS-232/422/485 Switch Headers

The headers determine that JCOM1A belongs to RS-232 (Default), 422, or 485.

JSEL1

RS-232 RS-422 RS-485

1-3 3-5 3-5

2-4 4-6 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

JSEL2

JSEL1

Note: Please notice Pin 9 of JCOM1A and of JCOM1B. JCOM1A: +5V;

JCOM1B: Ring indicator.