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Apple is against Bluetooth, but why?

September 14th, 2007 admin Comments off

First day with my shiny new iPhone, unlocked to work on Vodafone’s network – so far so good, pretty much loving it. Until I looked at the Bluetooth specs. Basically, this thing is only useful for mono headsets and carkits, and that’s it.

The iPhone has been certified under Bluetooth 2.0 + EDR, as can be seen in the BQB documents, but the PICS detail only handset and audio gateway profiles, with required signaling profiles such as RFCOMM, pretty much the bare minimum for a working Bluetooth hands-free system. What about the ton of other profiles, for example, A2DP, FTP, DUN…? Not included. The iPhone uses a CSR BlueCore4 Audioflash, which has 6MB of onboard FLASH memory, and could be upgraded provided that there is a host controller with access to the SPI port on the BC4. It seems that the iPhone uses Open Interface’s BLUEmagic 3.0 stack [PDF], which would imply an external host controller.

Now I’m starting to get confused – you usually choose a FLASH BlueCore if you intend to run software on it, be it CSR’s own stack, or a customized version of it. If you intend to use a host-based system, where the stack is handled by an external processor, you can buy way cheaper BlueCore ROM chips – and we’re talking between $1 and $3 a piece in savings. This may not seem much, but when multiplied it by Apple’s sales, you have a hefty sum. Below is a graphic that illustrates the differences between a host-based HCI system (left) and a standalone or ROM implementation (right):

bt_profile_diagram_hci

The big question still is – why is Apple so Bluetooth-unfriendly? Did they have certification problems and rushed through the bare minimum specs to claim Bluetooth compatibility? This seems strange as the iPhone was certified by CETECOM, which probably is the most experienced lab on Bluetooth certification in the world. Same applies to MacBooks and Mac Pros, they feature a few more profiles like FTP, but not A2DP. Hoping for a firmware update to fix this mess, over and out.


Categories: Apple, Bluetooth, Mac, MacBook Pro, Wireless, iPhone Tags:

Jawbone – the best Bluetooth headset ever

August 9th, 2007 admin Comments off

Just today UPS dropped off (well, I intercepted the driver in mid-flight, but that’s a different story) the Jawbone Bluetooth headset I was waiting for – and boy, does it work wonders! This has to be the best implemented piece of DSP technology I have seen. If you don’t believe in ‘official’ demos and blurb from jawbone.com (they are true), just check out this audio recording [WAV, 48kHz, 1.7MB]. The first part is recorder using my Mac with an unsquelched radio about 30cm from the headset, with the DSP turned off. I then turn it on, and the audio is recorded perfectly, with barely a hint of the background noise.

jawbone

How do they do it? I’ve not opened this baby up, as it’s too good-looking (and expensive), but it seems that they combine two directional microphones with a vibration sensor (the small white dot you see on the picture) that picks up bone-transmitted voice from your jaw (thus the name). By matching the vibrations, which are not enough to actually record sound, with the incoming audio from the microphones, they can take away the extra noise very effectively. I should know, as in my previous job, one of our biggest problems was noise and echo cancellation (I was responsible for electronics R&D at SouthWing, designing and testing Bluetooth headsets and other accesories) – and we could never completely kill feedback echo, and noise – forget it. Our designs were in the top league as far as audio quality and noise went, but try what I just did today and the whole recording would have been like the first half.

Good job, Aliph!

Categories: Bluetooth, Electronics, Toys & Gadgets Tags: