Hello,

Can anybody explain the details for the Sharp IR code format, specifically as it applies to the Denon receivers?

I was able to come up to speed on some of the specifics of IR codes from Barry Gordon's FAQ and documentation for GenIRDB (Thanks for the great discussion Barry!). However, I have some confusion with respect to the Non-repeating and repeating burst sequences in the Sharp IR and/or Pronto HEX format.

As an example of my confusion, I have downloaded the AVR3802 RC Code documentation from the Denon Website. It gives details for all of the commands and from what I can tell, the "Power On" command would consist of a "non-repeating" codeword: 01000 100001 11 00. Here, the first field (System Address) is "01000", the second field (Function) is "100001" and the other two fields seem to be fixed. I believe this would yeild the Pronto HEX equivalent command for entry as a learned IR code as follows:

0000 006D 0010 0000 000A 001E 000A 0046 000A 001E 000A 001E 000A 001E 000A 0046 000A 001E 000A 001E 000A 001E 000A 001E 000A 0046 000A 0046 000A 0046 000A 001E 000A 001E 000A 06D6

However, as a check to see if I constructed the code correctly (by looking at the Denon Receiver Discrete Codes on this website ([Link: remotecentral.com])

It seems to list both a "non-repeating" burst sequence (similar to the one I constructed above), followed by a 2-command repeating burst sequence (listed below in Denon's binary command format, in order to be concise):
01000 100001 11 00
01000 011110 00 11

This to me looks like a function called "Panel" in the Denon documentation, followed by the inverse of the Panel function (although the "System Address" field is not inverted).

To confuse me even more, I downloaded Tyler Ager's PCF file which contains learned codes for the AVR-3802 (Thanks Tyler!) at : [Link: remotecentral.com]

Looking at his PCF file, it appears that the learned IR code doesn't contain any "non-repeating" sequence, but contains a 2-command "repeating" sequence:
01000 100001 11 00 (Power-on command)
01000 011110 00 11 (Inverted Power-On Command).

I have also seen similar codes on this forum (like the thread relating to the Video Select function on the AVR-3801), which has the same command repeated 4 times (twice non-inverted, twice inverted ... interlaced):
01000 000110 11 00 ("Video Select" Function)
01000 111001 00 11 (Inverted "Video Select" Function)
01000 000110 11 00 ("Video Select" Function)
01000 111001 00 11 (Inverted "Video Select" Function)

So my questions are:
1) Is there any method to this madness, or are these IR codes pretty flexible (like the "Panel" command repeating after a "Power-on" command being innocuous) and can be constructed any number of ways?
2) Do you get enhanced reliability by repeating codes?
3) Does the Sharp format (or at least as it pertains to the Denon equipment) require repeating patterns to be inverted?
4) If the Sharp format requires repeating sequences to have an inversion on the second command, how come the "System Address" field is not inverted?

Thanks in advance to any help anyone can offer. I'd like to understand the structure of these codes better for my own customization needs. I hope this will also help me determine wether my learned commands look correct to me ... as a sanity check for debugging purposes.

- Confused