One of our AnalysIR users sent us this, for reference - may be of help to others in future.I spent some time reversing the codes from a Fujitsu mini split (heats and cools) remote (AR-REG1U) and captures a few notes (see attached .txt file). Might be of use to someone.
Details are as follows:
Fujitsu Mini Split Infrared Remote Control (AR-REG1U) Reverse Engineering
Hopefully, this will be of use to some others in future.Carrier frequency is not clearly known but various indications are that it is 38KHZ
Each button press sends either 128 bits or 56 bits.
The last two bytes of (two hex characters) are the checksum for both bit lengths.
The Analysir software decodes the bit stream as FUJITSU128_56AC and lists it as a "A/C" code
The Analysir software setting to decode is "LSB8"
For the 128 bit codes, the checksum algorithm ignores the first 7 bytes and the last 2 bytes (the last two bytes are the checksum)
The checksum for the 128 bit codes is 224 (decimal) minus the sum of the remaining bytes i.e. the sum of bytes 8,9,10,11,12,13,14
Why 224, who knows! I ran into a piece of Ruby code on the web (https://gist.github.com/GeorgeDewar/11171561) that decoded a Fujitsu remote
based on subtracting the sum of the selected bytes from 208. This led me
to try something similar and found that 224 was the magic number.
The checksum algorithm for the 56 bit codes is different; it is 255 (FF) minus the second to the last 2 bytes (the last 2 bytes/last
two hex characters is of course, the checksum itself.)
For example,
1463001010FE0930D0000000000020E0
The sum of bytes 8 through 14 = 00
So: E0 (224 - 00) = 224 or E0 (which is the checksum)
1463001010FE0930900400000000201C
The sum of the bytes 8 through 14 = C4
So: E0 - C4 = 1C (which is the checksum)
For example, 146300101009F6
the checksum is F6
The second to last two bytes are 09
So; the check sum is (FF - 09) = F6
FYI: Most AC units appear to be 38kHz. We have seen a very small number @ 33kHz & 36kHz