Demand for Voice Dialing Over BT?

[Guest MattimeoZ80]

Ever since I got my MPx220 I've been fairly annoyed at the fact that voice dialing over Bluetooth simply can't be done. The phone (and more specifically the MS BT Stack) seem to support most of the Handsfree Audio Gateway features such as redial, hang-up, etc. What's more, supposedly there are hooks to allow custom handling of these AT commands. So why isn't there a hack yet?

I just spent a few hours digging through MSDN, various newsgroups, etc., and I've come to the conclusion that getting this to work is indeed doable, apart from one possible hardware hurdle. From what I've read I have reason to believe that it is surmountable as well.

Which brings me to my question. Is there still a demand for this? I anticipate if I succeed, it will be after a LOT of work. I would of course release everything for free and if I fail I'll post my progress in case someone else wants to take it up. For me it's simply a question of whether it would be appreciated.

The most interesting part is that if it works, it should work for just about every other 2003SE phone with only slight modifications. From what I can tell so far it will involve writing a wrapper for a specific DLL that passes most calls through, but hooks into the voice-dial AT command. The only device dependent part would be what application to launch and how to handle the audio stream. And maybe that could even have a GUI with presets...

Thoughts?

[Guest mrslother]

Ever since I got my MPx220 I've been fairly annoyed at the fact that voice dialing over Bluetooth simply can't be done. 

.....

Which brings me to my question.  Is there still a demand for this? 

....

Thoughts?

<{POST_SNAPBACK}>

Short answer: it can not work on the MPx220 (and the Audiovox 5600).

Longer answer: Windows Mobile 2003 SE does support this but due to a manufacturer hardware bug the MPx220 isn't able to support this functionality. The problem was summarized to me by a tester in the WM team at Microsoft. He said that the MPx220 (and Audiovox 5600) have Bluetooth audio input is routted into an 8khz pin on the decoder chip. This quality is too low for any reasonable attempt at voice recognition, which requires at least 16khz samples. It was theorized that a fix could be attempted by the OEM modifying a driver to somehow route the signal into the 16khz channel via software, but the conclusion was that either it was impossible or not cost effective.

It sucks to be us MPx220 BT users.

[Guest MattimeoZ80]

Short answer: it can not work on the MPx220 (and the Audiovox 5600).

Longer answer: ...

It sucks to be us MPx220 BT users.

<{POST_SNAPBACK}>

That's what all of my research points to regarding a simple hardware solution; I'm rather surprised that Motorola dropped the ball on this one, phones 3 years old don't even have this limitation. Hardware "bug" riiight, it's only a bug if they fail to notice it. Sounds like they realized the limitation/problem and decided just to do nothing, either that or the phone really wasn't ready for production.

Do you know if the radio audio is then routed in hardware and not through the OS? Or is 8khz standard for Bluetooth voice? Do you know where I might find info about the specific Bluetooth/other chips in the MPx220? I'm more curious than anything.

Software seems like it might still be an option unless I'm missing something. I need to read up more on the distinction between software and hardware (and the limitations of software), but there is a reference Bluetooth Audio Software Driver included with Platform Builder 5.0. I've been able to get it to compile in eVC++ for CE 4.2, and when I have time I'm going to figure out exactly how it works and we'll see if that's a possibility. For now the driver doesn't load properly.

EDIT: It's looking like most if not all normal Bluetooth headsets are only 8khz. Also- I highly doubt 8khz is that big of a problem for the simple voice recognition employed by Smartphones, it's probably more that there needs to be an upsampling to 16khz. Also as far as I can tell headsets are limited to this low sample rate because they use SCO (synchronous) Bluetooth links which have a maximum speed of 64kbps, you simple can't get more in that speed. Really a software driver SHOULD be possible, I'll keep digging.

Edited December 27, 2005 by MattimeoZ80