[Bluez-users] position of multiple bluetooth dongles

[Bluez-users] position of multiple bluetooth dongles

[Marco Trudel]

Hello everybody

Maybe someone knows this:
If two bluetooth dongles are used (a class1 and a class2), could it lead to 
signal interfereces/problems if they're just above each other and both have 
to send a lot of data at the same time?

With "right above each other", I mean this:
http://www1.ch2.conrad.com/m/7000_7999/7100/7160/7162/716282_LB_00_FB.EPS.jpg
(dongle cases are removed).


kind regards
Marco


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Re: [Bluez-users] position of multiple bluetooth dongles

[GUILLON Gabriel]

As there is a very few chance that the use the same frequency at the=20
same time and send the same data, I think (hope?) there is no problem :)

Marco Trudel a =E9crit :
> Hello everybody
>=20
> Maybe someone knows this:
> If two bluetooth dongles are used (a class1 and a class2), could it lea=
d=20
> to signal interfereces/problems if they're just above each other and=20
> both have to send a lot of data at the same time?
>=20
> With "right above each other", I mean this:
> http://www1.ch2.conrad.com/m/7000_7999/7100/7160/7162/716282_LB_00_FB.E=
PS.jpg=20
>=20
> (dongle cases are removed).
>=20
>=20
> kind regards
> Marco
>=20
>=20
> -------------------------------------------------------
> SF email is sponsored by - The IT Product Guide
> Read honest & candid reviews on hundreds of IT Products from real users=
.
> Discover which products truly live up to the hype. Start reading now.
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>=20

--=20
Gabriel Guillon


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Re: [Bluez-users] position of multiple bluetooth dongles

[Marcel Holtmann]

Hi Gabriel,

> As there is a very few chance that the use the same frequency at the 
> same time and send the same data, I think (hope?) there is no problem :)

this might be one of 1600 per second. It is unlikely that the clock and
the device address will be the same.

Regards

Marcel




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Re: [Bluez-users] position of multiple bluetooth dongles

[Michal Semler]

BT 1.1 dongles may interference...
BT 1.2 only when comunication with 1.1 devices - 1.2 devices can never=20
interference

Michal

Dne =E8t 10. =FAnora 2005 18:13 Marco Trudel napsal(a):
> Hello everybody
>
> Maybe someone knows this:
> If two bluetooth dongles are used (a class1 and a class2), could it lead =
to
> signal interfereces/problems if they're just above each other and both ha=
ve
> to send a lot of data at the same time?
>
> With "right above each other", I mean this:
> http://www1.ch2.conrad.com/m/7000_7999/7100/7160/7162/716282_LB_00_FB.EPS=
=2Ej
>pg (dongle cases are removed).
>
>
> kind regards
> Marco
>
>
> -------------------------------------------------------
> SF email is sponsored by - The IT Product Guide
> Read honest & candid reviews on hundreds of IT Products from real users.
> Discover which products truly live up to the hype. Start reading now.
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> _______________________________________________
> Bluez-users mailing list
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> https://lists.sourceforge.net/lists/listinfo/bluez-users

=2D-=20
S pozdravem

Michal Semler


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Re: [Bluez-users] position of multiple bluetooth dongles

[Marcel Holtmann]

Hi Michal,

> BT 1.1 dongles may interference...
> BT 1.2 only when comunication with 1.1 devices - 1.2 devices can never 
> interference

let me correct this. AFH is not for detecting used frequencies of other
Bluetooth piconets. It only detects other wireless technologies, because
for itself it is already protected by the hopping sequence itself. If it
is the same hopping sequence it is the same piconet and thus it really
wants to listen to its traffic.

Regards

Marcel




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Re: [Bluez-users] position of multiple bluetooth dongles

[Marco Trudel]

Hello Marcel

so it's no problem? no mather of the bluetooth version of the dongle? no 
interference, respectively maybe a couple if thousands in a second?
corrected by rfcomm? the distance of two dongles doesn't matter?

regards
Marco


Marcel Holtmann wrote:
> Hi Michal,
> 
> 
>>BT 1.1 dongles may interference...
>>BT 1.2 only when comunication with 1.1 devices - 1.2 devices can never 
>>interference
> 
> 
> let me correct this. AFH is not for detecting used frequencies of other
> Bluetooth piconets. It only detects other wireless technologies, because
> for itself it is already protected by the hopping sequence itself. If it
> is the same hopping sequence it is the same piconet and thus it really
> wants to listen to its traffic.
> 
> Regards
> 
> Marcel
> 
> 
> 
> 
> -------------------------------------------------------
> SF email is sponsored by - The IT Product Guide
> Read honest & candid reviews on hundreds of IT Products from real users.
> Discover which products truly live up to the hype. Start reading now.
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> https://lists.sourceforge.net/lists/listinfo/bluez-users
> 
> 


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Re: [Bluez-users] position of multiple bluetooth dongles

[Marcel Holtmann]

Hi Marco,

> so it's no problem? no mather of the bluetooth version of the dongle? no 
> interference, respectively maybe a couple if thousands in a second?

ask an expert on the baseband level.

> corrected by rfcomm?

The error correction is done at the chip level. The ACL link is
reliable.

> the distance of two dongles doesn't matter?

If the distance is bigger, the chip must request more retransmission.
You won't see that in any of the BlueZ layers.

Regards

Marcel




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Re: [Bluez-users] position of multiple bluetooth dongles

[Marco Trudel]

Hello Michael

thank you a lot for this information.
Another question regarding this topic:

Does it help/make any difference if the two dongles have a distance of 
~11cm? Does this lead to equivalent/less interferences?
I have no idea about how radios send out their signals. I could imagine 
that if they spread their signal and there's another dongle just above the 
sending one that sends out a signal too, the interference is much worse 
than if they have a little distance, because the point of the problem is 
not right at the source.

Will rfcomm ensure the correctness of received data? something like a 
checksum and automatic retransmission of data if a brocken packet is 
recognized?

regards
Marco Trudel


Michal Semler wrote:
> BT 1.1 dongles may interference...
> BT 1.2 only when comunication with 1.1 devices - 1.2 devices can never 
> interference
> 
> Michal
> 
> Dne čt 10. února 2005 18:13 Marco Trudel napsal(a):
> 
>>Hello everybody
>>
>>Maybe someone knows this:
>>If two bluetooth dongles are used (a class1 and a class2), could it lead to
>>signal interfereces/problems if they're just above each other and both have
>>to send a lot of data at the same time?
>>
>>With "right above each other", I mean this:
>>http://www1.ch2.conrad.com/m/7000_7999/7100/7160/7162/716282_LB_00_FB.EPS.j
>>pg (dongle cases are removed).
>>
>>
>>kind regards
>>Marco
>>
>>
>>-------------------------------------------------------
>>SF email is sponsored by - The IT Product Guide
>>Read honest & candid reviews on hundreds of IT Products from real users.
>>Discover which products truly live up to the hype. Start reading now.
>>http://ads.osdn.com/?ad_id=6595&alloc_id=14396&op=click
>>_______________________________________________
>>Bluez-users mailing list
>>Bluez-users@lists.sourceforge.net
>>https://lists.sourceforge.net/lists/listinfo/bluez-users
> 
> 


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Re: [Bluez-users] position of multiple bluetooth dongles

[Michal Semler]

Safe distance is about 1m. in 1.1 dongles for 10 meters...10 meters for 1.1=
=20
for 100 meters.

M.

Dne po 14. =FAnora 2005 7:13 Marco Trudel napsal(a):
> Hello Michael
>
> thank you a lot for this information.
> Another question regarding this topic:
>
> Does it help/make any difference if the two dongles have a distance of
> ~11cm? Does this lead to equivalent/less interferences?
> I have no idea about how radios send out their signals. I could imagine
> that if they spread their signal and there's another dongle just above the
> sending one that sends out a signal too, the interference is much worse
> than if they have a little distance, because the point of the problem is
> not right at the source.
>
> Will rfcomm ensure the correctness of received data? something like a
> checksum and automatic retransmission of data if a brocken packet is
> recognized?
>
> regards
> Marco Trudel
>
> Michal Semler wrote:
> > BT 1.1 dongles may interference...
> > BT 1.2 only when comunication with 1.1 devices - 1.2 devices can never
> > interference
> >
> > Michal
> >
> > Dne =E8t 10. =FAnora 2005 18:13 Marco Trudel napsal(a):
> >>Hello everybody
> >>
> >>Maybe someone knows this:
> >>If two bluetooth dongles are used (a class1 and a class2), could it lead
> >> to signal interfereces/problems if they're just above each other and
> >> both have to send a lot of data at the same time?
> >>
> >>With "right above each other", I mean this:
> >>http://www1.ch2.conrad.com/m/7000_7999/7100/7160/7162/716282_LB_00_FB.E=
PS
> >>.j pg (dongle cases are removed).
> >>
> >>
> >>kind regards
> >>Marco
> >>
> >>
> >>-------------------------------------------------------
> >>SF email is sponsored by - The IT Product Guide
> >>Read honest & candid reviews on hundreds of IT Products from real users.
> >>Discover which products truly live up to the hype. Start reading now.
> >>http://ads.osdn.com/?ad_id=3D6595&alloc_id=3D14396&op=3Dclick
> >>_______________________________________________
> >>Bluez-users mailing list
> >>Bluez-users@lists.sourceforge.net
> >>https://lists.sourceforge.net/lists/listinfo/bluez-users
>
> -------------------------------------------------------
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=2D-=20
S pozdravem

Michal Semler


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