GPS - Re: A portable GPS should use standard mini-USB power (but which

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Re: A portable GPS should use standard mini-USB power (but which

Des O'Donoghue

2007-06-01, 10:33 pm

sarah bennett wrote:
> On Tue, 29 May 2007 01:20:31 +0000 (UTC), dold@68.usenet.us.com wrote:
>
>
> Hi there dold,
> Yes. This is a good point.
>
> I may have come on too strong on the environment. I would NOT throw an
> outdated portable GPS away just because it used outdated proprietary power
> supplies.
>
> But, I would only consider a modern power supply for any NEW portable
> electronics.
>
> And today, the ONLY modern power supply that is universally available is
> the USB 2.0 mini B standard.

But is it a standard ? It is a physical standard in terms of plug/socket
design but the outputs vary considerably. I had difficulty finding a
cigarlighter charger with a usb port that charged my Blackberry but when
I did it happily charged everything (my satnav, my bluetooth headset
[via adapter], my bluetooth gps, my K750i, my gameboys & DS) with the
exception of Motorola Razr and E-something-or-other.

Des O'Donoghue

2007-06-02, 7:33 am

Larry G wrote:
> On Jun 1, 5:00 pm, Des O'Donoghue <des_nos...@despod.com> wrote:
>
> so now you've got me confused again.
>
> I thought the device would automatically connect at minimal milliamps
> and the attempt to talk/negotiate with the USB port to get the correct
> amount of power - not too little and not too much.. but .. just
> right...
>
> how can that happen if the USB port is essentially a dumb 12volt
> receptacle?
>
> How do you know... in that situation how much power your unit is
> actually getting?
>

I don't know. I studied electronics a long time ago but promptly forgot
everything after the exams ;)

All I do know is that it all comes down to the current being output but
the Motorolas didn't want to play ball which proved the point that just
because the supplied charger had a mini-usb plug it didn't mean that it
would charge from other type chargers...

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