This is a question to tax the expertise of the remote(s) folks: many devices like AVRs and BDPs 9and even my CD jukebox) have these remove in/out 3.5mm [mono] minijacks. These are the same plugs that usually come out of RF/IP-to-IR receivers (although some are 2.5mm microjacks).
However, the IR transmission through the air is a binary digital signal modulate on a carrier frequency, normally in the 30-50kHz range. The receivers output this modulated signal through their jacks so that the attached IR emitters only need to be LEDs (and are not required to perform the modulation, because then they would need to know which freq to use).
I believe the input jacks on the A/V equipment wants the unmodulated binary signal, right? So feeding them a stream of bits that’s changing at up to 50kHz (yes, I know some go up to 500kHz) would confuse it…unless it performs some kind of low-pass filtering so that it can recover the original binary stream.
Some AVRs promote the fact that their IR output ports will retransmit codes for other devices, implying that any command it receives via IR (or the IR input port) that is NOT for it, will be retransmitted. (Unfortunately, I don’t think this is true for commands via IP, so my SC-67 controlled that way won’t send signals up to my non-IP Sony CD jukebox.)
So the question is: will these devices accept modulated signals into their IR ports? Or is it a case-by-case scenario that Yamaha will but Sony will not, or Pioneer receivers made after 2008 will and those before will not? I may end up trying this with the IP2IR I ordered, but I wonder if there are any precautions I should watch out for (like Port 3’s “blaster” mode).