Now that finally I have all elements together to actually use the device for its main intended purpose (most of the time it will be used as a music player) I had to discover that the base-level of noise is unacceptable high. It is impossible to listen to music with low volume, e.g. in a silent environment, as simply the base noise is filling your head. This of course depends on the sensitiviy of your headphones, but is already audible on my Koss Porta Pro (60 Ohms) and unacceptable on my CX-300 (16 Ohms). On my old Tornado (and even my Amadeus) it was just audible with the CX-300, but not with the Porta Pro.
I am much disappointed and only a very slight hope remains to increase the volume on one hand (the max volume is rather low compared to my Tornado) and decrease the sensitivity of the headphone on the other (serial resistor).
Sigh...
Seems to develop to a never ending story with this device :-( and I suspect that there will not be a happy end.
[Edit 20090108]:
I have not found any option in the registry for increasing the sound volume when the headset is connected. The sometimes reported action to set the valule in HKCU\ControlPanel\Volume to Volume=0xffffff is nothing but the place for the System Volume that is adjusted with the volume keys anyway. Even snapshotting the registry with and without headset connected and comparing these has not revealed an option.
As the noise level cannot be changed - and the volume not increased, I fear that was my short love story with this little gadget :-(
It still fits for anyone that has a lower sensitivity headset and does not require higher volume sound level there.
.
Showing posts with label Headset. Show all posts
Showing posts with label Headset. Show all posts
Tuesday, January 6, 2009
Monday, January 5, 2009
Tuesday, December 30, 2008
Hacking the USB Headset connector
[Updated 20090105 - see below]
Well - much to my disappointment, my device (claimed as - nearly new, factory refurbished) was delivered with a set of non-original parts. I received a Blackberry charger which has the option to exchange the plug for the mains-socket, so it also works in my continental sockets in Germany - no problem here, especially as all my other chargers (from my older HTC devices) also work.
BUT: the delivered headset was a cheap Motorola S200 replacement - which has the same plug, but different connectors inside. No way to get it working :-(
I knew that I will not use the original headset, but I need a blueprint to understand what is going on to build an USB-3.5mm adaptor. As I do not have that (yet - hopefully), I have checked other options to debug the duplicate purpose of the standard mini-USB (5 pin) plug.
The good part is that you have big variety of Motorola Headsets or adaptors that you can start working with - just look for the Razor-V3, it has the same physical connector.
The bad part is that the multiple use of the same socket for different purposes creates the need to have the device switch between these modes. Also here it is advised to have a look at related Motorola resources, e.g. here: http://wiki.openezx.org/EMU
Unfortunately the described options do NOT work for the E72 - but they give a clue on what to investigate...
Terminology:
The USB socket has 5 pins + shield, sometimes the numbering is 1,2,3,x,4, but I prefer to number the pins in sequence, i.e. 1,2,3,4,5 - just like the EMU wiki above does.
Findings:
Thanks to the community in Taiwan, see this post, the connection strategy is now settled :-)
Continuing my discussion above the "protocol" on pin(3) is very simple - just connect a resistor (below about 250 ohm) to grounds - that's all - the device will go into headset mode (can also be seen at HKLM\System\State\Hardware - the value of the "Headset" property changes to "1".
After the device is in headset mode, pin(3) can be released again (what I did to identify the other speaker channel and microphone connection). So the final result is then for the numbered pins of the USB connector (1-5):
Mind that the drawing in the Taiwanese post labels the "V+" and "GND" incorrect - they have to be reversed. The "NC" (microphone) pin is close to the - (GND) pin.
Well - much to my disappointment, my device (claimed as - nearly new, factory refurbished) was delivered with a set of non-original parts. I received a Blackberry charger which has the option to exchange the plug for the mains-socket, so it also works in my continental sockets in Germany - no problem here, especially as all my other chargers (from my older HTC devices) also work.
BUT: the delivered headset was a cheap Motorola S200 replacement - which has the same plug, but different connectors inside. No way to get it working :-(
I knew that I will not use the original headset, but I need a blueprint to understand what is going on to build an USB-3.5mm adaptor. As I do not have that (yet - hopefully), I have checked other options to debug the duplicate purpose of the standard mini-USB (5 pin) plug.
The good part is that you have big variety of Motorola Headsets or adaptors that you can start working with - just look for the Razor-V3, it has the same physical connector.
The bad part is that the multiple use of the same socket for different purposes creates the need to have the device switch between these modes. Also here it is advised to have a look at related Motorola resources, e.g. here: http://wiki.openezx.org/EMU
Unfortunately the described options do NOT work for the E72 - but they give a clue on what to investigate...
Terminology:
The USB socket has 5 pins + shield, sometimes the numbering is 1,2,3,x,4, but I prefer to number the pins in sequence, i.e. 1,2,3,4,5 - just like the EMU wiki above does.
Findings:
- Connecting a resistor in the range of 50 to 200 kB between (5+Shield) and (1) will raise the level at (1) from 0,3V to the full power of the battery (you can drive a light with this!) for exactly 10 seconds.
- Pin (3) (the middle one) will generate a stepping voltage output (1 Hz) as long as (1) is up - here I suspect an action is required to confirm the operation mode.
- nothing more - I had to give up here...
- The temporary presence of (a fully powered) supply voltage at pin (1) and the activity at pin (3) may indicate an active wired headset (just like the Motorola). It is however impossible to tell without a real E72 headset at hand...
Thanks to the community in Taiwan, see this post, the connection strategy is now settled :-)
Continuing my discussion above the "protocol" on pin(3) is very simple - just connect a resistor (below about 250 ohm) to grounds - that's all - the device will go into headset mode (can also be seen at HKLM\System\State\Hardware - the value of the "Headset" property changes to "1".
After the device is in headset mode, pin(3) can be released again (what I did to identify the other speaker channel and microphone connection). So the final result is then for the numbered pins of the USB connector (1-5):
- Must be connected with a resistor less than 200 kOhms (but more than 10k - not to drain the battery) to ground. The voltage will rise briefly to battery level (so if you short cut this to ground it may kill it) but then drop back to 0,16 V to stay there. I suspect that accepting calls with the headset button will introduce new functionality here...
- Speaker channel (l,r not checked, source indicates right here) - must be connected to a speaker or a pulldown resistor at device-headset connection time.
- Speaker channel (l,r not checked, source indicates left here)
- Microphone channel (checked to work with Audionotes)
- Grounds
Mind that the drawing in the Taiwanese post labels the "V+" and "GND" incorrect - they have to be reversed. The "NC" (microphone) pin is close to the - (GND) pin.
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