can BT create N independent channels?

can BT create N independent channels?

[james pruett]

I am writing an Android APP using BT for a control application.

Q: If I am on a BT-headset call already, can I create a second BT-connection?

Eg, will the stack allow two independent BT audio channels?

I want normal calls in one channel, and I create a second signalling
channel for an unrelated purpose. I know there is Serial protocol, but
I want to avoid that if possible (Serial devices are more expensive
than audio devices...) I am going to send the audio into a DTMF
decoder to get ON/OFF control bits only.

Thanks for any leads!
jim pruett
wikiSPEEDia.org

Re: can BT create N independent channels?

[Ash K]

Hi James,

Comments bellow:

On Tue, Aug 9, 2011 at 12:14 PM, james pruett <gpscruise@gmail.com> wrote:
> I am writing an Android APP using BT for a control application.
>
> Q: If I am on a BT-headset call already, can I create a second BT-connection?
>
> Eg, will the stack allow two independent BT audio channels?

BlueZ does allow you to do it, but Android framework does not have
this facility in it (Since it was meant to handle all the normal
cases, which is to handle one call). You probably have to hack into
Android to create two audio channels.

Also remember that HF/HS audio means SCO connections and not all
controllers support multiple SCO connections (Not sure if two
controllers can provide you parallel SCO connections, though I know
controllers supporting 2 SCO connections connecting two different
controllers. Let me know if you find out if some one provides 2 SCOs
between 2 devices).

>
> I want normal calls in one channel, and I create a second signalling
> channel for an unrelated purpose. I know there is Serial protocol, but
> I want to avoid that if possible (Serial devices are more expensive
> than audio devices...) I am going to send the audio into a DTMF
> decoder to get ON/OFF control bits only.

Why can't you use same AUDIO channel for both audio data and DTMF
tone? A phone connection will not be established until you get
ring/dial tone, on ring AUDIO will be sent to DTMF encoder and switch
the AUDIO destination to speakers once the connection is established.

>
> Thanks for any leads!
> jim pruett
> wikiSPEEDia.org
> --
> To unsubscribe from this list: send the line "unsubscribe linux-bluetooth" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at  http://vger.kernel.org/majordomo-info.html
>



-- 
Ash

Re: can BT create N independent channels?

[Mikel Astiz]

Hi Ashok,

Could you please list some hardware alternatives (usb dongles) that do 
support multiple SCO connections? (in my case, the application has 
nothing to do with Android)

Besides, how can be checked if your hardware supports this feature?

Regards,
Mikel

On 08/09/2011 10:02 PM, Ash K wrote:
> Hi James,
>
> Comments bellow:
>
> On Tue, Aug 9, 2011 at 12:14 PM, james pruett<gpscruise@gmail.com>  wrote:
>> I am writing an Android APP using BT for a control application.
>>
>> Q: If I am on a BT-headset call already, can I create a second BT-connection?
>>
>> Eg, will the stack allow two independent BT audio channels?
> BlueZ does allow you to do it, but Android framework does not have
> this facility in it (Since it was meant to handle all the normal
> cases, which is to handle one call). You probably have to hack into
> Android to create two audio channels.
>
> Also remember that HF/HS audio means SCO connections and not all
> controllers support multiple SCO connections (Not sure if two
> controllers can provide you parallel SCO connections, though I know
> controllers supporting 2 SCO connections connecting two different
> controllers. Let me know if you find out if some one provides 2 SCOs
> between 2 devices).
>
>> I want normal calls in one channel, and I create a second signalling
>> channel for an unrelated purpose. I know there is Serial protocol, but
>> I want to avoid that if possible (Serial devices are more expensive
>> than audio devices...) I am going to send the audio into a DTMF
>> decoder to get ON/OFF control bits only.
> Why can't you use same AUDIO channel for both audio data and DTMF
> tone? A phone connection will not be established until you get
> ring/dial tone, on ring AUDIO will be sent to DTMF encoder and switch
> the AUDIO destination to speakers once the connection is established.
>
>> Thanks for any leads!
>> jim pruett
>> wikiSPEEDia.org
>> --
>> To unsubscribe from this list: send the line "unsubscribe linux-bluetooth" in
>> the body of a message to majordomo@vger.kernel.org
>> More majordomo info at  http://vger.kernel.org/majordomo-info.html
>>
>
>