User Guide

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10. RS-232 Protocol
10.1 Introduction
This document describes the hardware interface spec and software protocols of
RS232 interface communication between ViewSonic LFD and PC or other control
unit with RS232 protocol.
The protocol contains three sections command:
• Set-Function
• Get-Function
• Remote control pass-through mode
※ In the document below, “PC” represents all the control units that can sent or
receive the RS232 protocol command.
10.2 Description
10.2.1 Hardware Specication
ViewSonic LFD communication port on the rear side
(1) Connector type: DSUB 9-Pin Male (or 3.5mm barrel connector)
(2) Pin Assignment
(3) Use of crossover (null modem) cable for connection
Male DSUB 9-Pin
Pin # Signal Remark
1 NC
2 RXD Input to Display
3 TXD Output from Display
4 NC
5 GND
6 NC
7 NC
8 NC
9 NC
frame GND
3.5mm barrel connector
(alternative for limited
space)
Pin # Signal Remark
Tip TXD Output from Display
Ring RXD Input to Display
Sleeve GND