I recently replaced a Pioneer 1015TX receiver with an Onkyo TX-SR705 that has a direct IR-IN port on the back.

The Onkyo does not respond reliably using the direct connection from the MRF,
regardless of the trim-pot setting for that port.
If I use a flasher emitter using the same port, the Onkyo responds every time.

FWIW, I have two MRF-300's in the house and have Zero RF interference (antennas remotely located).

Is this an issue that people encounter in the field using direct IR ports? It's possible that the IR detection circuitry on the Onkyo is more forgiving than the direct in port, but I have no idea.

Both the MRF and Onkyo are on the same outlet so I doubt it's a grounding issue.

Any thoughts would be appreciated!

I posted this same issue a few post down. I never could get mine to work via the Onkyo IR port on the back of the receiver. I think the port is working because it also has an IR Out port and that will pass the IR signal to another IR blaster. If you find out the problem, please let me know. Chad

To the best of my knowledge, the IR in port on the back is actually tip/ring/sleeve, meaning a mono 3.5mm cable would ground out the positive terminal of the IR IN port and disable all IR control. For proper operation, you'd need to splice a mono 3.5mm cable to a stereo 3.5mm cable like the one included with the RF antenna. With only a total of 6 different combinations of ways to wire 2 wires into 3 wires, trial and error should find that bulletproof hardwired IR control we all know and love. I'm too lazy to pull out my Integra and try it, but then again, I'm using RS-232 and that would be too much work getting IR codes set-up anyway. If you want me to try it myself, PM me, and I'll pull forward a display model.

Wow, Onkyo must be different than Integra then. Integra DVD players ship with a mono cable and they work perfect with the MRF-260 on the full outputs. Maybe that is one of the differences besides the warranty.

Works fine from an RTI RP6 controller to the the an Onkyo SR705 direct IR using a mono 3.5 cable. So maybe something with the MRF-300?

I have read in the past that previous versions of Denon receivers had problems with Universal Remote RF base stations because of the address bit sent with the IR codes.

Perhaps this is the same issue.

I did get mine working fine. You just have to work with ir adjust screws. If it is not set just perfect it will not work. Chad

^that is correct. ive done that same setup on multiple occasions for different customers, and it is VERY sensitive to the pot setting on the mrf. play with it for a little while and it will work wonderfully.