Powering a sat-nav, difference in USB leads??

[dyzio]

Hi all,
I have a Garmn Nuvi 250w nav, it's powered via a mini USB port from a cigarette lighter socket. All was fine until I've borrowed it to my bro, who managed to damage the adapter. Ok I thought, I'll get a new one, however:
- the new one, only switches the garmin into "communicating with PC" mode and doesn't allow to use it as a navigator at the same time.
I've noticed it's the same when trying to recharge it from a PC, some leads allow to recharge and use the nav at the same time while others just switch it to the "communicating" mode...

Are there 2 different types of usb cables or something? How can they be told apart before buying (apart from testing)

Cheers

[the white rabbit]

I can't answer your problem but I can reassure you that this is indeed a real life pain in the ****. I found one in my huge box of leads that worked and labelled it. Couldnt see a reason.

[dyzio]

How much do you want for it? ;)

[the white rabbit]

I'm hanging on to it, I am afraid.