ok, so i've been putting in a lot of hours reading and figuring out as much as i can about all this stuff. a very steep learning curve.

so i'm using the sony remote RM-AX1400. after i choose a "preset" in the software, it spits out a txt file with codes in it for many of the buttons/functions. since marantz provides a spreadsheet with the RC5 & RC5X info in it, i was able to figure out how those codes were generated.

here's what i figured out and what i'm still unable to figure out.

for example, here's a code and its formatting (a single line entry) from that file that the remote editing software output (this is to toggle power state on/off):
0\\POWER\\29100000000C00000081\\\\

it works. so i looked at the marantz spreadsheet, which lists not only a VERY LONG hex code that i have no idea how to use, but it also lists
system: 16
command: 12
extension: -- (there isn't one)

well, 16 in hex is 10, and 12 in hex is 0C, and i discovered that the 29 is the "protocol" and it's used by marantz and also some phillips AVRs. so the code is structured this way:

protocol (2 digits, hex) + system (2 digits, hex) + '000000' + command (2 digits, hex) + '000000' + (either '81' or '83' and it really doesn't matter which for any of the commands i'm executing)

so even though the software's output file was seriously lacking in functions, i was able to construct additional codes, make new line entries into the file, and then use the software to assign a button to the code i'd added to the text file. that was awesome. i can successfully use the remote to do almost everything i will ever want to do. EXCEPT...

what i figured out is how to use the RC5 codes, ones without extensions. what i can't figure out is WHERE do i add the extension for the codes that include extensions? for instance, discrete power on and power off are, of course, the same system and command and differ only by the extension. if i want to program a macro to turn everything off, i need to figure that out. if i want to be able to switch input source by using the "input next" code or the "blu-ray input" code, i need to know how to add line entries that include the extension.

none of the codes included for any of the preset files has an extension in it for me to reverse engineer the location of this in the string. i think that's partly because the remote is older? i'm not sure. but i can tell from perusing a lot of sites online that this formatting is very common. marantz just happens to not be quite common enough for me to figure this out specifically.

"input next" is kind of at the top of my list of things to make work. the marantz spreadsheet lists this for "input next":
system: 16 (in hex, 10)
command: 00 (in hex, 00)
extension: 13 (in hex, 0D)

i've already tried doing it by adding in the "0D" into the middle and padding it with another 6 zeros.

like this (spacing for readability only): 29 10 000000 00 000000 0D 000000 81

that didn't work.

i've also tried adding "0D" in after the command "00", replacing two of the zeros in the padding that trail the command, and a variety of permutations that seemed a possibility. there's so much info out there about lots of other much more complicated ways of programming remotes, but mine is actually REALLY simple. well, once i know where to stick the "0D" (or any extension).

but a google search for "marantz rm-ax1400 rc5x" is not helpful. at all. i hope someone here is just nerdy enough to know how i do this. and don't point me to that spreadsheet in the file section of this website that outputs these types of codes---i already looked there, but for some reason it is missing the "29" protocol that marantz and phillips both use.

thanks in advance for your help!!!