User:Alisonken1/Pjlink

PJLink is a standard for basic control and configuring of a Projector over a network interface. It was developed by the Data Projector Group within the Japan Business Machine and Information System Industries Association (JBMIA). The aim of the standard is to define a manufacturer and model-independent interface for the configuration and monitoring of video displays.

Definitions

The following subsections detail the specific terminology and descriptions used as well as special characters in communications between the controller and terminal.

Terminology

Term	Description
Command	Packet from controller to change a terminal setting
Controller	Device/software used to send commands to remote projector/display
Class	Version of applicable PJLink standard
Header	Start byte indicating a PJLink data packet
Packet	Network data byte(s) sent in one communication transfer
Parameter	Variable-length portion of packet that contains control setting or reply status Controller: Query or setting value Terminal: Status information or error code
Query	Packet requesting status or information from terminal
Reply	Packet sent from Terminal to Controller
Separator	Byte in the packet that separates the command from the parameter
Terminal	Remote projector/display being controlled

Special characters

Mnemonic	Hex Code	Meaning	Description
%	0x25	Header	Start byte of PJLink packet
<cr>	0x0d	Terminator	End byte of PJLink packet
<sp>	0x20	Space	Separator byte in command packet
=	0x3d	Equal sign	Separator byte in reply packet

Communication

Communication is via the TCP protocol. A command or query packet is sent from the controller, and a reply is returned by the terminal. The header, class, command, separator, and terminator will all be in the ASCII character set. The parameter may be either ASCII or UTF-8 character set. Maximum size of a packet is 136 bytes.

Packet Detail

A PJLink packet has the following characteristics:

Header	Class	Command	Separator	Parameter	Terminator
1 byte	1 Byte	4 bytes	1 byte	0-128 bytes	1 byte

Example query to request PJLink class terminal supports:

"%1CLSS<sp>?<cr>"

Example reply for PJLink class terminal supports:

"%1CLSS=1<cr>"

External links

Category:Internet Protocol Category:Display technology Category:Projectors