Overview

This article explains how to control ViewSonic Large Format Displays (LFDs) using RS‑232 or LAN commands. It includes hardware specifications, communication settings, command structure, and examples of Set/Get commands.

This content is based on the official ViewSonic LFD RS‑232 & LAN Protocol Specification v3.3.2.

What the Protocol Document Covers

1. Hardware Connection Details

The document explains:

• RS‑232 port type (DB9 male or 3.5mm jack)

• Required cable (null‑modem/crossover)

• Pinouts for both RS‑232 and LAN ports

• Supported LAN control settings (TCP port 5000, WOL port 9)

This section helps technicians verify wiring, adapters, and network configuration.

2. Communication Settings

The protocol uses fixed serial settings:

• 9600 baud

• 8 data bits

• No parity

• 1 stop bit

LAN control uses:

• TCP/IP

• Port 5000

• No login credentials

This ensures compatibility with control systems like Crestron, Extron, AMX, Q‑SYS, and custom scripts.

3. Command Structure

The document defines the exact byte format for:

• Set commands (change display settings)

• Get commands (retrieve display status)

• Reply messages (“+” for valid, “–” for invalid)

Technicians rely on this to build correct command strings.

4. Full Command List

The protocol includes all supported control functions, such as:

Power

• Power on/off

• Power lock

Input Control

• HDMI1–HDMI4

• VGA

• DisplayPort

• Type‑C

• Android (embedded source)

• Input cycling

Display Adjustments

• Brightness

• Backlight

• Contrast

• Color mode

• Freeze

Audio

• Volume

• Mute

Security / Lockouts

• Button lock

• Menu lock

• Remote control enable/disable/pass‑through

Video Wall / Tiling

• Tiling mode

• Bezel compensation

• Position mapping

Date/Time Settings

Function On/Off Controls

(Backlight, Freeze, Touch)

This section is essential for automation programming and service diagnostics.

5. Status & Information Queries

The document also includes GET commands for:

• Current input

• Power state

• Brightness/volume levels

• MAC address

• IP address

• Serial number

• Firmware version

• Smart sensor data (temperature, humidity, PIR, light)

These are used for monitoring, remote diagnostics, and system health checks.

6. Remote Control Pass‑Through

The protocol supports IR pass‑through mode, allowing the display to forward remote‑control codes to external devices via RS‑232.

7. Wake‑on‑LAN (WOL)

The document includes the required WOL packet format for powering on supported displays over the network.

Who Should Use This Document

This protocol specification is intended for:

• AV technicians

• System integrators

• Automation programmers

• IT administrators managing signage or meeting‑room displays

• Anyone needing direct serial or network control of ViewSonic LFDs

Additional Tools for Technicians

ViewSonic vController Application

In addition to the RS‑232/LAN protocol document, ViewSonic also provides vController, a Windows‑based software tool that allows technicians to control compatible ViewSonic displays without manually sending serial commands.

What vController Offers

• GUI‑based control of power, input, audio, and display settings

• Multi‑display management

• Scheduling features

• LAN and RS‑232 support

• Ideal for technicians who prefer software control instead of raw command strings

Downloads:

vController User Guide

vController Application