I have a device (Light controller) that is working ok in ProntoPro IR mode, but when I change it to RF mode using philips RF extender device doesn't works.

Carrier frequency is 455KHz and example of codes is :

0000 0009 0000 0023 0014 0069 0014 0032 0014 00c3 0014 0069 0014 0069 0014 0069 0014 0069 0014 0069 0014 0069 0014 0069 0014 0069 0014 0069 0014 0069 0014 0069 0014 0069 0014 0069 0014 0069 0014 0069 0014 0069 0014 0069 0014 0069 0014 0069 0014 0069 0014 0069 0014 0069 0014 0069 0014 0069 0014 0069 0014 0069 0014 0069 0014 0069 0014 0069 0014 0069 0014 0069 0014 07d0

As you can see there are 35 burst pairs, pulses are of 44us.

Other devices are working ok in both modes IR & RF.

Thanks.

JEMA

I forgot, Device is from Lexel elextronics. It is an IHC controller.

calling doctors fine, Houston and Oulianov.....i think he speaks your language(s).

I have no experience with the extenders. My guess is that they cannot reproduce a 455KHz carrier but I do not know that for certain.

Bomber Jim did run some tests for me to confirm that the RF preample contains the carrier frequency as well as CH & ID.

Sorry, Dr Fine is a specialist and RF extenders are outside my specialty. I have no idea whether an RF extender can reproduce 455Khz. I'd EXPECT it to be unable to reproduce the 44 microsecond pulses even if it could handle the 455Khz. But I'm just guessing. I don't have specific knowledge about the minimum pulse width it can handle.

I have checked IR signal from RF extender LI970 by learning via Crestron CNXLIR - the signal was OK:

Crestron format =
09 00 23 16 0014 0032 0068 007C 00C1 07C1 0201040202020202020202020202020202020202020202020202020202020202020205

Pronto format =
0000 0009 0000 0023 0014 0068 0014 0032 0014 00C1 0014 0068 0014 0068 0014 0068 0014 0068 0014 0068 0014 0068 0014 0068 0014 0068 0014 0068 0014 0068 0014 0068 0014 0068 0014 0068 0014 0068 0014 0068 0014 0068 0014 0068 0014 0068 0014 0068 0014 0068 0014 0068 0014 0068 0014 0068 0014 0068 0014 0068 0014 0068 0014 0068 0014 0068 0014 0068 0014 0068 0014 0068 0014 07C1

I think, it is quite similar to be recognizable. BUT 0014 is really short to be a good pulse length for this frequency, the ordinal one is 005B for B&O, so you can have a troubles to replay and receive this singal in ANY point of the tract!
And, just in case - please, select CH and ID above 0 (i.e. CH=1 and ID=1) and set the same at corresponded device at CCF. Check that red eye flashes while you hit the corresponded buttons on Pronto.

Thanks Eigeny,

As you say IR data sended by RF extender is the same as original data sended by pronto in IR mode, so where is the problem ?.

Which is the difence selecting other ID & Channels ?

Red led is flashing when I transmit data.

Thanks again.

OK, it is mean that RF transmission is near to successful!


1. I have learned that code successfully from n-th try, so it may be a trouble of it replaying by RF extender due to very short impulses. In this way I recommend to try to increase all bursting lengths a little and decrease gaps for the same number of periods (the sample is +/-000Ch):
0000 0009 0000 0023 0020 005d 0020 0026 0020 00b7 0020 005d ...

2. Is it the only RF fault in this installation? If yes, it most likely that any other electrical appliance depress it (the RF detector at RF extender is very wideband :(, so it not functions when my 2.4GHz phone tries to locate a network or when a nasty noname x10 dimmer nearby is around of 50% dim :(( ).
So, try to expel that devices from suspicion one by one!

3. May be, IR emitter (if you use it instead of RF extender itself) is not positioned well. Try to play with its location correspondently to device's IR receiver.

4. Try to read the FAQ here, and the manual - sometimes...

5. How do you obtain those codes? May be you can locate another ones?


If nothing help, don’t worry - you will be neither first nor last victim of this treacherous device: try to search "RF extender" at this forum, and all searched subjects will name it "trouble source"!

Once I have a joke: new Hi-Fi Marantz receiver with Philips RC5 codes becomes inoperable by Marantz RC9200 with corresponded Marantz RF extender RX-77 (developed by Philips)!

44µS is awfully short but I doubt that it's critical. The timing data is probably the difference between rising edges (i.e. pulses).

I'm sure that the duration of 44uS is not critical. My worry was that the attempt (in a general system not designed for durations that short) to encode/modulate, decode/demodulate and reproduce a duration that short would fail entirely, rather than just fail to get the duration close to 44uS.

I'm sure the timing data is NOT (as you seem to be saying) the full wavelength (rising edge to rising edge). That design would make the majority of simple IR protocols fail.

The frequenct data is represented as a full wavelength. 455Khz has a wavelength around 2.2uS. The timing data that includes that 44uS is expressed in Pronto Hex as multiples of that full wavelength representing half waves at that level, but in the RF encoded signal is probably expressed as actual durations rather than numerically encoded.

If I understand Eigeny correctly (far from certain), he transmitted that signal through an RF extender and captured the end result in Pronto Hex and it was virtually identical to the orriginal, meaning for his RF extender there is no reason to worry about 455Khz nor about the 44uS pulses.

I'm lost at this points on several aspects of this, including the relationship (if any) between Eigeny's RF extender and Jema's, and why (given such good reproduction of 44uS pulses) Eigeny suggests increasing the pulses and decreasing the gaps.

That's because Eigeny understands that the only thing that matters is the time between rising edges.

I am not stating that as a universal rule as you seem to think. It depends on the protocol. The NEC protocol documentation (I cited a datasheet to an NEC chip elsewhere.) makes it clear that only the time between rising edges matters.

44µS is tough for some microcontrollers to resolve.

heeeyyyyyyy.........i thought you guys didn't know nuthin' 'bout this here stuff.

..........or were those just liability disclaimers up there?    

Thanks Everybody.

I'll try to modify pulse length.

CCF Codes I got from the manufacturer of the original system Lexel.

I'll turn off all RF systems (there are two wireless micros but af freq. near 180MHz).

Anybody knows how is the data sended to RF extender?, description of header and data itself.

Thanks again.

There is a short preamble which contains the CH, ID, & Carrier Frequency. The preamble repeats 3 times with no gap. Then, after a 5ms gap, the data envelope is exactly the same as for IR. I have not attempted to reverse engineer the preamble - my only interest was in confirming that the preamble preceded the actual data envelope - others had speculated that the RF Extenders used a far more elaborate, encrypted methodology.

My guess is the RF Extender(s) decode the preamble and if the CH & ID match the extender setting, repeat the data envelope using the carrier called for in the preamble.

There is an "oscilloscope" screen shot of a preamble at the bottom of this page...

[Link: laser.com]

The screenshot may illustrate a problem with this approach. There is no lead-in to the preamble and all of the pulses are relatively short. The RF receiver has to set its AGC based on the preamble itself and, as you can see in the screenshot, only the last copy of the three approaches clarity. A 4-5ms leadin pulse would set the AGC and make for better reception.

Reception is usually better by the time the actual signal starts but if the extender hasn't determined that the preamble is addressed to it, it doesn't repeat the data as IR. IMO this is an amateurish design that might appear reliable on a test bench but is inherently unreliable in the real world.

There have been numerous reports of poor RF range with the extenders. Without one of the RF capable remotes and an extender to test, it's hard to say why. It could be that the RF signal from the remote is weak. It could be that the antenna/RF receiver in the extender are weak. It's likely to be a bit of both.

Again, I've never seen an RF Extender so the following is speculation.

RF receivers have a maximum data rate which varies with the type of receiver. For the ASK (Amplitude Shift Keying) receivers that I use extensively, this is 4800bps which equates to a 208µS bit period. Even if you assume a 25% duty cycle, this is getting very close to the 44µS pulse width. I've never tested the minimum pulse width it can detect but would not be surprised if it had trouble with a 44µS pulse.

This message was edited by Dave Houston on 05/15/03 08:45.

Finally I made all test and it doesn't works.

Eigeny, I can grow 44µS pulses up to 130µS reducing gaps as well and via IR is working but when I select RF (different channels and IDs) its impossible to run.

Reception of IR commands seems to be with very high tolerance, when I changed pulse values those are not critical.

What could happen ?

Thanks