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IR vs IRDA
Posted: Mon May 29, 2006 10:46 am
by ElizabethD
I know that the wavelength of IRDA signals is different from IR signals we talk about here by about 10-12%. Still, is it possible for IR signal to make IRDA port on a computer respond, especially if they use (guessing here) the same NEC1 protocol?
By 'respond' I don't mean anything reliable or designed, but rather interference, enough to cause the PC do goofy things when a remote for, say, TV is used.
Re: IR vs IRDA
Posted: Mon May 29, 2006 11:00 am
by johnsfine
ElizabethD wrote:I know that the wavelength of IRDA signals is different from IR signals we talk about here by about 10-12%.
I didn't know that, but even if it's true it must not create a significant incompatibility. IrDA hardware can send and receiver remote control signals.
ElizabethD wrote:Still, is it possible for IR signal to make IRDA port on a computer respond, especially if they use (guessing here) the same NEC1 protocol?
IrDA is a protocol as well as a set of hardware. That protocol is nothing like NEC1.
ElizabethD wrote:By 'respond' I don't mean anything reliable or designed, but rather interference, enough to cause the PC do goofy things when a remote for, say, TV is used.
Sounds unlikely. I don't know for sure that the IrDA receive hardware and software in a PC aren't so horribly misdesigned that they mistake a totally dissimilar signal for an IrDA signal. But NEC1 and IrDA are both common enough, such an error should have been found and fixed quickly.
I can't tell whether you are trying to understand/avoid a problem or whether you're trying to generate a response.
A JP1 remote can generate IrDA signals, so with decent documentation on what IrDA signals you want to send (which I don't know where to get) you could send those signals.
Posted: Mon May 29, 2006 12:54 pm
by ElizabethD
johnsfine wrote:I can't tell whether you are trying to understand/avoid a problem or whether you're trying to generate a response.
The ONLY reason for this post is to understand just a bit and to see whether a conflict is conceivable. I saw a post someplace about a claim that a TV remote affects a PC and wondered whether it's likely. There was no details there.
The wavelength info is from Mike
https://www.hifi-remote.com/forums/viewtopic.php?t=2921
The extent of my knowledge about IRDA is from the handful of posts I found here after search.
I made up the NEC1 idea based on some lirc file I found for a Packard Bell computer remote and a mention of Akai TV.
http://lirc.sourceforge.net/remotes/pac ... ckard_bell
Just goofin' around

I have no idea what I'm looking at and it's too hot to do yardwork or clean the house.
Posted: Mon May 29, 2006 5:50 pm
by Mark Pierson
ElizabethD wrote:it's too hot to do yardwork or clean the house.
The grass (or is it weeds) is over a foot tall, the sink is full of dishes, and the family has no clean clothes... but Liz is sitting there controlling all her IR devices with her trusty JP1 remote!
You go, girl! 8)
Posted: Mon May 29, 2006 7:48 pm
by ElizabethD
Mark Pierson wrote:The grass (or is it weeds) is over a foot tall
Priorities, Mark! Weeds take on a whole different meaning when you think of them as wildflowers
I don't expect John to answer any more, there's almost no need. But do you read his answer as 'interference is unlikely but can occur'?
Posted: Tue May 30, 2006 1:33 am
by underquark
Remember, if you've got weeds then you've got (or had) sunshine and that should be considered as a possible source of interference. Although IrDA is meant to be fairly tolerant in the visible spectrum, bright light can affect mice or other tracking devices.