Viewsonic CDE4302 User Manual

26

This document describes the hardware interface spec and software protocols of RS232 interface 

communication between ViewSonic Commercial TV / Digital Signage 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 send or receive the RS232 

protocol command.

11.2.1. Hardware specification
Viewsonic TV communication port on the rear side:
(1) Connector type: DSUB 9-Pin Male 
(2) Pin Assignment

Male DSUB 9-Pin
(outside view)

1

NC 

2

RXD

Input to Commercial TV or DS

3

TXD

Output from Commercial TV or DS

4

NC

5

GND

6

NC 

7

NC

8

NC

9

NC

frame

GND

* Use of crossover (null modem) cable required for use with PC

[Special case]3.5mm barrel 

connector 

Tip

TXD

Output from Commercial TV or DS

Ring

RXD

Input to Commercial TV or DS

Sleeve

GND

11.2.2. Communication Setting
- Baud Rate Select:  9600bps (fixed)
- Data bits:

8 bits (fixed)

- Parity:

None (fixed)

- Stop Bits:

1 (fixed)

11.2.3. Command Message Reference
PC sends to Monitor command packet followed by “CR”. Every time PC sends control command to the 

Monitor, the Monitor shall respond as follows:
1.  If the message is received correctly it will send “+” (02Bh) followed by “CR” (00Dh)
2.  If the message is received incorrectly it will send “-” (02Dh) followed by “CR” (00Dh)