Nokia 6500 Classic stereo headphones adapter problem

Only guessing, but USB spec doesn't include analogue signals - just digits and DC. So again I'd guess the Nokia unit includes electronics.

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You're right Dave - the Nokia unit which works does include electronics. There's a microphone piece as well as a dial to change volume, and a button to advance track number.

Does this document..

=2E.clarify for your whether any mini-USB attachment with a 3.5mm stereo adapter would require some electronics in-between to convert a digital to analogue signal? That's assuming I've understood what you suggest the problem might be.

Yes. It could be you could modify the Nokia one to use headphones of your choice - ie using the Nokia electronics. But that PDF doesn't give the spec of the headphones they supply, and the power amp may not be suitable for standard ones.

It might be possible to source a USB input headphone amp which will drive conventional ones. Although it might be bigger than the phone itself ;-)

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ide quoted text -

Dave,

Thank you for all this, it's incredibly helpful. I had considered the possiblity of adapting an existing set of Nokia headphones to have a

3.5mm jack coming out of the electronics unit instead of the earbuds themselves, but this would be slightly messy and ultimately result in a lot of wire.

As you appear to be something of an expert, at least compared to myself, do you know of anywhere who offers a service that would rehouse the section of the electronics piece that converts to the digital signal in small plastic casing with a 3.5mm jack for me?

Despite my poor soldering skills, I'd do this myself, except when I took my official Nokia headset apart it had what appeared to be fiber optic wiring instead of anything I could take a soldering iron too. I imagine this is standard now to allow thinner leads, but doesn't help me solve my problem.

Many thanks as always, myself and others are hanging on a solution - schnide

I'm afraid that would be the price to be paid. It's really not practical to make things as a one off as small as the factory can.

Heh heh - enthusiastic amateur would be nearer it. With *some* expertise in *some* things.

Afraid I don't. It's the sort of thing I might well attempt for myself - but not a stranger. And don't really know of anywhere providing such a service - which would be very costly anyway, due to the time involved for any one off.

It's probably a mixture of fibres and copper to provide extreme flexibility and strength. You normally terminate this sort of flex with a crimped joint.

If many want this I'm surprised an accessory maker hasn't supplied what you need.

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On Wed, 21 May 2008 08:15:15 -0700 (PDT), snipped-for-privacy@btinternet.com put finger to keyboard and composed:

You may be able to find your cable pinouts here:

To convince yourself that your adapter is a digital device, you could connect it to your PC with an appropriate cable and then use Microsoft's UVCView.exe or usbview.exe to display the device characteristics. I'm assuming that your adapter would not be a host. If it is a host, then the above won't work.

I'm using Windows 98SE. In Control Panel's Device Manager, under the Power properties for the USB Root Hub, I see that my USB flash drive reports that it requires 100mA max current. I'm not sure, but I suspect that Win XP may be able to report the actual current draw.

UVCView and Usbview both report that my USB phone is bus powered and requires 200mA MaxPower. These utilities may also be able to tell you who is the real manufacturer of your devices.

If you can't find the above utilities, contact me via email.

- Franc Zabkar

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text -

Thanks Franc - this looks helpful. I'll try it tonight and will report my findings back here.

As an aside, I'm fairly sure from what I've read on Nokia documentation that the Nokia 6500 Classic can do both a host and non- host mode. That might not be important, but I've mentioned it just in case.

here:

text -

Okay, well here are what the two programs reported. Does this give any indication to a solution?

All help or suggestions gratefully appreciated,

schnide

On Sun, 25 May 2008 07:02:18 -0700 (PDT), snipped-for-privacy@btinternet.com put finger to keyboard and composed:

AFAICS, the only pertinent info is that your phone's USB port, when configured as a client, is externally powered and can draw up to

500mA, which is USB's limit. I was thinking that you could connect your audio adapter to your PC as a client, if indeed that is how it is designed, and then interrogate it in similar fashion. If the PC shows that your audio device demands more than 100mA, then that would be a problem according to Nokia's documentation.

For host configurations, Nokia's documentation states that ...

"The Nokia 6500 Classic and Nokia 8800 Arte mobile phones, which are based on the Series 40 platform, support USB audio devices. These mobile phones will be referred to throughout the document as the Series 40 USB hosts."

"The Series 40 USB host can sustain current up to 100 mA. It is recommended to draw as little current as possible to increase playback or speaking times. Based on recommendations by Nokia, an amount of 100 mW should not be exceeded during operation at maximum volume."

- Franc Zabkar

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Thanks for your continued help Franc - Nokia themselves, meanwhile, are so far coming back with nothing but attempts to try and fob me off.

So if I understand this right, I have my headphones I want to plug in, and the mini-USB to 3.5mm audio adapters bought from eBay. Are you suggesting I get a mini-USB to standard USB converter, plug the audio adapter into that, the headphones into *that*, and then run the two programs again - posting my findings?

*bump*

On Tue, 27 May 2008 06:36:31 -0700 (PDT), snipped-for-privacy@btinternet.com put finger to keyboard and composed:

All I'm suggesting is that you somehow determine the current demand of each of your devices, with and without the headphones attached. The only way I know how, other than to intercept the cable with a multimeter, is to query the device's properties using your PC. To this end you will need a suitable cable.

For example, you can see the maximum current requirement of your device in Win XP by going to Device Manager and querying your Root Hub's Power Properties. It should list the power requirements of each attached USB peripheral. If you can determine the vendor and product IDs for your peripheral, then these numbers may reflect the chip rather than the device manufacturer, in which case you may be able to find a datasheet with an application diagram ...

- Franc Zabkar

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