Re: 28. Nw readers, RF intruders in wireless alarm systems

["Roger" <rumble@xxxxxxxxxxxxxxxxx>]

Not quite sure what you are trying to say here, you're English is good but
sometimes a bit garbled. Anyway, my technical knowledge in this area is
abosolute. I am an engineer working in both hardware & software. Over the
years I have been a part of various design teams producing to manufacture
various equipment utilizing wireless technologies and using rolling code for
encryption. I am a design enginner and have been for over 20years.

What about you?


<-bull@shit> wrote in message
news:eb3ta1p4fkqrblkcvbcfaejd2b2mlj54qo@xxxxxxxxxx
>
> Rubbish oh yes you are to elementary to understand wireless, poor guy.
>
> Rolling code is of any use ONLY when the transmitted data is valid.
> During Radio Frequency Interference (RFI) there is NO VALID
> INFORMATION included ID.
>
> What is your technical knowledge and what measurement tools do you
> have beside your little wet finger in the wind?
>  Your professionals wet finger idiocy is coming from head to bottom!
>
>     RFI brain probe
>          \  /
>       ____\/____
>      / ___  ___ \
>     / / @ \/ @ \ \
>     \ \___/\___/ /\
>      \____\/____/||
>        \Bottle/
>         |neck |      Pro's in
>        /      \       Pissing
>       /        \       Contest
>      |          \
>      |           |
>     /            |
>     |            ===.    10 mW
>     \           OO   \    output
>      |           |    o    power!
>      |          /      o
>      \_________/        o
>         || ||      \___,,,__ /
>         || ||       |  WAS  |O  WAS = Wireless Alarm System
>        _||_||_      \_______/
>
> The desire to not understand wireless alarm techniques
>     is far less intelligent than
>                           the inability to understand them
>
>
> On Mon, 13 Jun 2005 17:53:13 GMT, "Roger" <rumble@xxxxxxxxxxxxxxxxx>
> wrote:
>
>>What total rubbish! You do not understand rolling code or its true
>>purpose.
>>And as for the rest of it...delays - what a joke. You make me laugh you
>>really do. Anyone reading this diatribe should simply ignore it. Take it
>>from me that the guy doesn't know what he's talking about.
>>
>>
>><-pull@shoot> wrote in message
>>news:ojdpa11eadvtap4nkqvo5krfkaivipittb@xxxxxxxxxx
>>>
>>> Radio Frequency (RF) intruders.
>>>
>>> The whole RF spectrum is divided and regulated by international
>>> committees who define the allowances on each frequency.
>>> The Wireless Alarm Systems have free multi user "shared" frequencies
>>> assigned with no waranty that it is free for communication at any
>>> requested time.
>>> Keeping in mind that only one operator can transmit on the same
>>> frequency at the same time, a protocol is laid-out to circumvent the
>>> shared frequency restrictions.
>>> Each user has to respect some transmission rules like:
>>> - Limit the transmit power;
>>> - Each transmission has to have an identifier;
>>> - transmit in a BURST transmission mode,
>>> to mention the most essentials.
>>>
>>> Limited transmission power.
>>> By limiting the transmission power the signal reception range is
>>> reduced and by consequence the possible mutual interference on that
>>> frequency.
>>>
>>> Personal identifier (ID).
>>> As multiple users uses the same frequency and in order to retrieve
>>> only the information belonging to hiss personal system, each user
>>> identifies themselves during hiss transmission with a unique ID.
>>> Some transmitters uses ID rolling codes, the code changes each time in
>>> order to make sure that at repetition he has a unique ID.
>>> Realize that sometimes this rolling code may not be unique, the
>>> individual receivers have to keep trace of the temporary intruder ID
>>> in order to retrieve only hiss data.
>>> This requires multiple transmission/reception attempts before true
>>> validation of the corresponding ID and by consequence causes a
>>> reception DELAY.
>>>
>>> Burst transmission.
>>> Burst transmission is one way to circumvent mutual interference.
>>> Each transmitter sends hiss data information during a small period of
>>> time hoping that the frequency is unoccupied while he transmits.
>>> When two or more transmissions occur at the same time, interference
>>> is generated and the receivers are disturbed, they can't decode the
>>> data information.
>>> This is not a real problem, the transmission is repeated several time
>>> with the hope that at some time during the repetitions the frequency
>>> is free.
>>> This require multiple transmission/reception attempts before data is
>>> passing true, by consequence this causes a reception DELAY of the data
>>> involved.
>>>
>>>
>>> The whole burst transmission protocol has restrictions, the burst
>>> length and repetition rate, the number of possible systems and
>>> different types using the same frequency and more..
>>>
>>> Now, back to the header, intruders.
>>> As described above, the validity of data transmission of all
>>> transmissions using the shared frequency spectrum are depending on the
>>> respect of the burst transmission requirement/principle.
>>> If one, lets call them INTRUDER, uses a different protocol and
>>> transmits without the respect of the burst principles, the whole
>>> frequency utilization goes bingo in the distance range of hiss
>>> transmitter.
>>> That's the case during Radio Frequency Interference (RFI).
>>>
>>> Hope this clarifies a little the wireless alarm system shared
>>> frequency operation fragility.
>>>
>>> NOTE: I don't mind if "so called professionals" explain it in a
>>>      better and more detailed way but it never happened...
>>>      Criticism is easy, explaining instead...
>>>
>>> Paul
>>>
>>>
>>
>