Re: C-Bus / IR / Bluetooth / WiFi / X-10 / Idratek / EIB

[Mal Lansell <mal@xxxxxxxxxxx>]

ZWave uses 900Mhz - does anything else use that these days?  I know
the
old analog cordless phones did, but what about the digital ones?

X10 RF is 433Mhz - again I don't know what else uses this.

Mal


Keith Doxey wrote:

>Hi Chris
>
>
>
>>'making a list of emc (electromagnetic compatibility) problems, 
so-far
>>I have :
>>
>>* C-Bus dimmers blind X-10 dimmers, at least when in
close-proximity
>>
>>
>>
>
>Probably due to the filtering employed by the C-Bus dimmers. EMC
>compatability requires that equipment does not generate mains bourne
>interference and is not suseptable to misoperation resulting from mains
>bourne interference. Given that phase controlled dimming involves
chopping
>up the mains thereby causing loads of interference it is not
unreasonable to
>expect that a manufacturer of such a product will go to great lengths
to
>resolve that problem.
>
>X10 uses powerline communications as its data bus which means that it
>DELIBERATELY PUTS INTERFERENCE onto the powerline. There are many
pieces of
>equipment that will cause problems with X10. Basically ANYTHING that
uses a
>switch mode power supply will either attenuate the X10 carrier or worse
>totally obliterate it.
>
>My advise would be to avoid X10 completely especially for a new
>installation. For retrofit, many have no other option. Whilst my X10
has
>been pretty good for the last 7 or 8 years (I only have a few modules)
there
>have been times when it just gives up the ghost for seemingly no reason
>whatsoever. My new laser printer is the latest culprit, had to fit a
filter
>to it.
>
>
>
>>* compact fluorescent lamps of a certain age, within the same room,
and
>>for a while soon after being switched-on, talk to the IR of my
hi-fi &
>>persuade it to do things
>>
>>
>>
>
>Depends greatly on the IR receivers. As you have said in the past, your
Hifi
>is quite old and probably uses a discrete IR photodiode with additional
>circuitry to proces the signal. Modern IR Photodetector modules are
tiny
>little 3 pin devices that incorporate all the required circuitry. They
are
>exceptionally good at rejecting unwanted signals and will self adjust
to
>"remove" continuous signals that would normally interfere
with reception
>although this does reduce the sensitivity a bit.
>
>As Phil pointed out in another reply, this can affect IR repeates as
well
>but tend to be more of a problem with systems that will accept a wide
range
>of IR frequencies as the filtering cannot be as tight. The
"friendly"
>receivers are designed for a more restricted IR frequency and can
therefore
>filter the signals much better.
>
>IR protocols have also improved over the last few years and modern
codes are
>much more resiliant to false decodes. Some early IR codes were very
basic
>with little or no error checking and as a result, if the received
signal
>looked something like it should then the equipment would respond.
Because
>modern devices have so many functions, the codes are now much more
complex
>and have better error checking.
>
>I ALWAYS prefer a wired solution over one that doesnt use wires because
it
>tends to work 100% of the time and the only thing that will stop it is
>physical damage.
>
>Wireless (either RF or IR) solutions have their place in the overall
scheme
>of things but should not be seen as the preferred way. As RF devices
become
>more prevelent the radio spectrum will become congested and at best,
data
>rates will fall due to retransmission because of corrupion/collisions.
>
>If you run out of bandwidth on a cable, adding "n" cables
will give you "n"
>times the amount of bandwidth. The same isnt true for RF, the only ways
are
>release more radio spectrum or reduce RF power so "RF
networks" can be
>closer together.
>
>Hope that helps
>
>Keith
>
>
>
>
>Yahoo! Groups Links
>
>
>
>
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