Re: a phantom signal source

[nobody@xxxxxxxxxxxx (Dave Houston)]

The ESM1 does not do a thorough manchester check but only counts the number
of 1 bits and 0 bits that follow a 1110 (presumed to be a start code). Thus
11101111111111100000000000 is only one of many non-X10 sequences that might
cause the X10 Good LED to illuminate.

"Jeff Volp" <JeffVolp@xxxxxxx> wrote:

>I did not monitor X10 line traffic while testing the Cellet cellphone
>charger:
>
>http://jeffvolp.home.att.net/x10_info/x10_Cellet_noise.htm
>
>However, if you look at the 3rd photo down, you can see the ESM1 giving a
>solid "X10 Good" indication when the charger was loaded with 20 ohms.  I was
>testing how well the XTB-IIR AGC rejected the noise, and I did not see it
>accept the signal as valid even though the ESM1 seemed to be happy with it.
>
>Jeff
>
>"Dave Houston" <nobody@xxxxxxxxxxxx> wrote in message
>news:4757eb05.231349328@xxxxxxxxxxxxxxxx
>>A while back there was a thread here about the possibility of noisy switch
>> mode power supplies (SMPS) spontaneously generating valid X-10 PLC codes.
>> Bruce Robin sent a noisy SMPS (in a charger) that was blocking X-10
>> activity
>> to Jeff Volp who ran some tests. AFAIK those tests failed to show any
>> spontaneously generated X-10 codes.
>>
>> There was a recent thread on Smarthome's Insteon forum that, in part,
>> discussed phantom PLC codes being logged that went away when a CFL (with
>> an
>> apparently noisy SMPS) was removed from the mix. Further investigation
>> found
>> that the source of the apparently spontaneous codes was actually an ACT
>> CR134 coupler/repeater. When it was replaced with a plug-in passive
>> coupler,
>> the phantom codes disappeared. Another factor was that the phantom codes
>> only appeared after a valid Status Request was transmitted.
>


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