RS-232 Protocol
This document describes the hardware interface spec and software protocols of RS-
232 interface communication between ViewSonic LFD and PC or other control units
with RS-232 protocol.
The protocol contains three command sections:
• Set-Function
• Get-Function
• Remote control pass-through mode
NOTE: Below, "PC" represents all the control units that can send or receive the
RS-232 protocol command.
Description
RS-232 Hardware Specification
ViewSonic LFD communication port on the rear side:
1. Connector type: DSUB 9-Pin Male (female or 3.5 mm barrel connector)
2. Use of crossover (null modem) cable for connection
3. Pin Assignment:
Male DSUB 9-Pin
(preferred)
Female DSUB 9-Pin
3.5 mm barrel connector
(alternative for limited
space)
Pin #
Signal
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
Item
Signal
Tip
TXD
Output from Display
Ring
RXD
Input to Display
Sleeve
GND
55
Remark
Remark