IRForum

Posted: **Thu Apr 29, 2021 8:27 pm**

My go-to reference for IR protocols is the following webpage
http://www.hifi-remote.com/johnsfine/DecodeIR.html
I've come across an issue with the Sony 20 bit protocols. The IRP definition according to the above reference for 20 bit Sony is

{40k,600}<1,-1|2,-1>(4,-1,F:7,D:5,S:8,^45m)+

First of all, that "+" should be a "3" because you have to send all Sony codes 3 times in a row.

But apart from that, the end the "^45m" means that the entire signal should be 45000 uSec long but if you happen to have a code that was all "1" then the extent of the signal would be 39000 which means the gap between successive sends is only 6000. Most decoders would not recognize this as a gap between individual signals.

Does anyone have a genuine Sony 20 bit remote and can tell me if the gap between successive sends a fixed amount or does it vary depending on the overall extent? What is a reasonable gap between the three Sony repeats?

Posted: **Thu Apr 29, 2021 10:54 pm**

It seems the 45 mSecs is correct for 20 bit SONY as well.

Code: Select all

$40:2400,600,1200,600,1200,600,1200,600,1200,600,1200,600,1200,600,600,600,600,600,1200,600,600,600,1200,600,1200,600,1200,600,600,600,600,600,600,600,1200,600,1200,600,1200,600,1200,10133,2400,600,1200,600,1200,600,1200,600,1200,600,1200,600,1200,600,600,600,600,600,1200,600,600,600,1200,600,1200,600,1200,600,600,600,600,600,600,600,1200,600,1200,600,1200,600,1200,10133,2400,600,1200,600,1200,600,1200,600,1200,600,1200,600,1200,600,600,600,600,600,1200,600,600,600,1200,600,1200,600,1200,600,600,600,600,600,600,600,1200,600,1200,600,1200,600,1200,10133,2400,600,1200,600,1200,600,1200,600,1200,600,1200,600,1200,600,600,600,600,600,1200,600,600,600,1200,600,1200,600,1200,600,600,600,600,600,600,600,1200,600,1200,600,1200,600,1200,10133,2400,600,1200,600,1200,600,1200,600,1200,600,1200,600,1200,600,600,600,600,600,1200,600,600,600,1200,600,1200,600,1200,600,600,600,600,600,600,600,1200,600,1200,600,1200,600,1200,;

The above is from a SONY DSLR camera remote and repeats every ~45mSecs. Also 20 bits with multiple repeats.

From memory I believe I have seen from-time-to-time signals where the 3 bursts were not required...but best to be safer with 3.
I always work on the basis that any info regarding IR remote control is only solid, if directly from the manufacturer & even with that I have occasionally seen inconsistencies between datasheets from the same manufacturer for the same protocol.

Most decoders would not recognize this as a gap between individual signals.
...unless it was a SONY device which was expecting that. I would also suspect that SONY would design their commands to be shorter on average vs lots of 1s.

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