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Consumer IR - Learning Mode



Dear Experts,

I have a PDA with a consumer IR capable beam. Read an article about
using 115 baud 7-bit w/ stop bit and no parity and the famous value
0x5B to replicate 3x the frequency modulation of common remote
controls. They also do some manchester coding and have some timing
gaps that are specific to their brand. My brand, JVC, seems to use a
different gap for the wait states (AKA silent states).

This led me to think, how can I go about learning the code of another
device. So I took their sample code, flipped it around, looped tightly
on reading the IR Port, and took account of how many bytes could be
read before blocking. Most of the bytes were the famous 0x5b, however
in some there was the 0x7b.

I don't understand the topic of frequency modulation well enough to
figure out where to go from here and wanted to solicit advise. In
short, I want to learn basic remote commands from a remote control via
a software on my PDA by reading the IR Comm port. Once I compile the
data, I'd like to play it back. My first attempt of the tight loop
dumped an array of number of reads and time between the reads, but
when I went to play it back it did not operate the TV in the way I was
expecting. This means something in my procedure, assumptions, or both
is incorrect. Anyone have background here that could explain the
procedure from reading the IR Port when a remote is aimed at it with a
button pressed to learning the code and timings and then playing back
with IR Port writes?

Thank you!


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