I have an IR543 (X10 RF interface) for controlling the lights in my media room. But it stops working when my HP LC3200N LCD TV is on, due to IR interference. Up until today, if I wanted to adjust the lights using my universal remote, I had to turn off the TV first.

But I also discovered by testing that if the IR543 was completely isolated from visible light emissions from the TV, it remained operational even if the TV is on, and even if the IR543 is still close to the TV. So I considered ways to isolate the IR543 from the TV's light emissions. I read about the PAC IR-X, how it operates at either 40KHz or 53KHz. Hmm. The IR-X might be able to ignore the LC3200N's IR emissions while the IR543 is too cheaply engineered to ignore the same off-frequency IR emissions.

I ordered a PAC IR-X IR extender--$30 including shipping.

Received the IR-X today and hooked it up. Powered it with a spare AC adaptor that outputs 11V DC. Mounted the IR extender's IR sensor on the front of my AV receiver. Taped the IR extender's IR emitter on the front of the IR543 with black electrical tape. (The black tape is sufficient to isolate the IR543 from whatever light (visible and IR) coming from the TV.)

Problem solved. Now my LCD TV and my IR543 cooperate.

This might also work for some plasma TVs which apparently have the same issue with the IR543.

I have a Panasonic Plasma and the IR 543. When I had them plugged into the same outlet, the IR543 wouldn't turn on any of my lights. I plugged it into a different outlet and it worked fine. The IR543 is directly under my Plasma TV but now has an extension cord to the other outlet.

Don't know if its the same problem you were having, but it solved my problem.

I tried that first, and also tried an RF filter on the power line where it made sense. No help. My issue was definitely an IR noise issue. The IR-X fixed it.

This one really had me going too. I even bought another IR543, but it exhibited the same problem. I've read numerous forums concerning this issue, but no one seemed to really have a definitive answer as to how to fix the problem. After much experimentation, I think I've found the solution.

The problem seems to be the amount of ambient infrared light reaching the IR543 sensor. The device is actually being "locked up" by this ambient infrared light. Since we can't see infrared, it's impossible to detect it's origin.

The solution was to limit the amount of ambient infrared light reaching the sensor. I first tried using a piece of opaque tape with a small hole in the middle of it in front of the sensor. Both of my IR543 units functioned perfectly after this mod.

I've produced a set of two black-on-clear stick-on P-touch labels with different hole sizes that I can send to anyone who is experiencing this problem to modify their unit.

Let me know if you need one.

How much extra latency is there since it has to repeat the signal?

I can't believe I didn't think of this on my own. Works great. Just so other people know the pac device is a little on the expensive side. I bought this at tiger direct for $16 and can control up to 8 devices (if i had a need to). I slapped the emitter onto the front of the IR-543 and I just put the ir543 into the box that this device came in, so it's in pitch black.

Ultra U12-41498 IR Repeater:
[Link: tigerdirect.ca]

Works reliably and is low latency.