Projector Control - RS232 / USB?

Question

I noticed that a number of projectors have RS232 or USB ports that can be used to control the functions of the projector, i.e. switching inputs and turning power on and off. Does anyone know if there is an API to manage these functions programmatically?

I use Java, but especially with RS232. I guess this does not matter, since the protocol will be at a much lower level. If there is no “standard” around (which I suppose will not) what will be the proposal? Right now I'm thinking of defining a projector control interface for the functions that I want, and then letting people write classes for external control of the projector and drop them in place (maybe pick them up on the fly, using the new Watchservice API.) are there any flaws with this that i don't see?

Essentially, I'm looking for a document (if one exists) that describes serial protocols for performing basic functions on different projectors.

Answer 1

Incredibly helpful answer to AVForums:

almost the entire transfer is a simple telnet rs232 text string. not all ascii, but most of them. you will read the calculated parity and checksum bytes .. but in fact you just need to send the string and the projector will do what it says. Some people find it easier to communicate by sending hex bytes, esp, if they use odd characters without ascii, but most of them are simple ascii, followed by a translation string. The fact is that if you use hex, you can support every code, including ascii, if you are going to open the platform, start there.

many models have different iputs, etc., but in most cases all manufacturers will use the same rs232 lines to turn on, turn off, enter 1-7 or hdmi 1-2-3, etc.

keep it simple if you can, just by monitoring the power status and input selection, and you have a chance to get 80% of ordinary projectors without too much effort.

ohh and 9600, 8n1 for almost everything.

More details:

as promised ... these are some on the offset for wholesale .. on is the next ascii text followed by a carriage return (if you don’t know .. there is no code for the 'ENTER' key .. it is represented by the old carriage return typewriter functions and line by line), they are represented by hexadecimal values ​​0d for CR and 0a for LF) hex

for the letter "I": 49 and "R": 52

ABOUT

* 0IR001 or in hexadecimal on the next line.

2a 30 49 52 30 30 31 0d

Off * 0IR002 or 2a 30 49 52 30 30 32 0d

for input HDMI1 * 0IR017 \ r

2a 30 49 52 30 31 37 0d

Panasonic AX200 .. differs in that it has a text value, but with a hexadecimal character to start the command '02' and hex '03' to finish one .. "are not used in the command, just to show its ascii text inside them

ABOUT

: 02 "PON": 03

02 50 4f 4e 03

Off

: 02 "POF": 03

02 50 4f 46 03

HDMI1 input

: 02 "IIS: HD1": 03

02 49 49 53 3a 48 44 31 03

Sony is weird, there is no real ascii there at all ... just a complete stop and a question mark .. it's just hex.

Power on

a9 17 2e 00 00 00 3f 9a

Power off

a9 17 2f 00 00 00 3f 9a

HDMI1

A9 00 01 00 00 04 05 9A