[ltp] Cardbus USB2 card for Thinkpad X30

[Simon Williams]

trotter wrote:
> I was reading on another email group that you can add a USB2 port to old
> laptops with a cardbus interface.
> 
> Since the x30 has only usb1 I was thinking of getting one.
> However on the same email group user recommended that an interface with a
> power brick was used as usb2 with some devices attached can burn out the
> motherboard.

I'm pretty sure this is a myth. Even if the cardbus socket doesn't have 
a current limiter, the USB card should have. The USB standard only 
requires that USB ports provide 500mA. Lots of ports are limited to 
this, including: the motherboard ports on my PC, the front panel on my 
PC, my USB hubs without the power adapters attached, and my T23's 
docking station port.

I have a USB to 2.5" IDE hard disk adapter which only has one USB plug 
on it. 2.5" disks usually require up to 1A. Plugging this into any of 
the above ports results in it just not getting enough power to spin up. 
You can hear it trying, but the USB port is clearly limiting it. 
However, my T23 (and other ThinkPads) will power it fine from the rear 
ports. I have used it like this extensively and no damage has occurred.

The same thing happens with all my USB 2.0 cardbus cards. If the power 
adapter isn't attached to it it will limit itself to 500mA and the disk 
won't power up.

> I have searched for a cardbus with a power adaptor bus i can not find one.
> 
> Has anyone come across them?

*All* USB cardbus/pcmcia cards have a power socket. The only difference 
is whether it has a mains transformer on the end, or a USB plug. I 
personally find the USB plug much more useful as I can then use it when 
mobile, and the USB 1.1 ports on my T23 can give it all the power it needs.

I have a Belkin one which has a mains plug on it. It's the traditional 
style that sticks out the side of the laptop. What I like better though 
is ebay item #290343244562 - a low profile card that doesn't stick out. 
Much more useful for a laptop. Unfortunately they're only available from 
HK at the moment, but I've bought 5 so far and not had any problems.

Hope this helps.

Simon