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23 Posts

01-16-2013

Australia

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Re: TPT2 has USB port power issue

2013-02-12, 0:49 AM

@AllRed

 

Dell Latitude 10.

 

About 9mm larger bezel all round, slightly thicker (o.6mm), slightly heavier (~60g) even has a replaceable battery (option of a 6-cell).

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26 Posts

01-06-2013

United States

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Re: TPT2 has USB port power issue

2013-02-12, 12:08 PM

@Patanjali,

 

Yeah seems thats the only option right now. (Asus was onto something with the AsusVivo Tab Smart but decided not to inlcude a digitizer).

 

I think i'll just stick to the TPT2, hasn't failed me yet, but this usb issue can really be handled in a better way.

 

Lenovo customer care has be worried.

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648 Posts

07-20-2009

United States of America

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Re: TPT2 has USB port power issue

2013-02-12, 17:03 PM

Boom. In their review, Laptop Magazine plainly states in the cons "USB port doesn't support bus-powered hard drives or peripherals". THANK YOU Laptop Magazine for pointing this out the the general public. 

http://www.laptopmag.com/reviews/tablets/lenovo_thinkpad_tablet_2.aspx

 

Still a great device (they rate it 4 out of 5 stars). Lenovo should just be upfront and explicitly state this, rather than leaving that major asterisk off the page and hoping people don't care. 

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39 Posts

01-08-2009

France

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Re: TPT2 has USB port power issue

2013-02-12, 23:23 PM

Engadget also reported the USB issue in its review !

 

http://www.engadget.com/2013/02/11/lenovo-thinkpad-tablet-2-review/

 

I hope Lenovo will quickly state on this issue...

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165 Posts

12-10-2008

United States of America

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Re: TPT2 has USB port power issue

2013-02-13, 0:00 AM

Personally, I could live with the USB power issue, but it even if I decided to order a TPT2, it's simply not available at the moment. The estimated delivery time is stated as more than 4 weeks on Lenovo's US store for some time now. So either there's an overwhelming demand from corporate customers, or the device went back to the drawing board.

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4036 Posts

12-22-2008

Canada

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Re: TPT2 has USB port power issue

2013-02-13, 21:13 PM

wrote:

Boom. In their review, Laptop Magazine plainly states in the cons "USB port doesn't support bus-powered hard drives or peripherals". THANK YOU Laptop Magazine for pointing this out the the general public. 

http://www.laptopmag.com/reviews/tablets/lenovo_thinkpad_tablet_2.aspx

 


That review also says in the body, "Unfortunately, the port provides 2.5 watts, so many bus-powered devices won't work with it."

 

I don't know how the reviewers determined that the TPT2's USB provides 2.5W but let's assume that they're correct. After all the USB 2 specification requires a powered USB port to provide 5VDC±5% at a maximum of 500mA. That's 2.5W (5 x 0.5 = 2.5.)

 

So it seems the TPT2 USB port complies with the USB 2 specification. IMO the reviewer's "Con" criticism is bogus.

 

Here's my theory about why external HDDs and DVD burners won't work without additional power: Those external HDD/DVD drives rely on being able to draw more current than the USB specification actually provides for.

 

That assumption works on devices that have multiple USB ports because the 5V line has to be able to provide 500mA times the number of USB ports. In effect the HDD/DVD makers assume they'll be able to "steal" the extra current their devices need from unused USB ports or USB ports that are being used for low-power devices like keyboards and flash drives. As long as the total current drawn by all USB devices is less than 500ma times the number of ports, everything works fine. It's also possible that on desktops and notebooks there's lots of extra current on the 5V line for non-USB purposes like internal HDDs and DVDs so external devices can "steal" some of that power. (The Y-cable provided with some external drives is presumably there in cases where each USB port follows the USB spec fastiduously providing a maximum of 500mA indpendently of the other USB ports.)

 

But none of this is the case on the TPT2 because it doesn't have any provision for adding internal devices or for powering more than one USB port. As a result there's no extra current for HDD/DVD drives to "steal." 

 

If my theory is correct, then this isn't Lenovo's fault. They've built the TPT2's USB port in full compliance with USB specs. The fault lies with manufacturers who assumed their external device could "steal" the additional power beyond the 2.5W the USB spec allows them.

 

It would be interesting to see how much current the typical external HDD/DVD devices draw from the USB port. Perhaps someone with ammeter and a spare USB cable that they can hack, will do some measurements on both a TPT2 and other ThinkPads that have multiple USB ports.


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648 Posts

07-20-2009

United States of America

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Re: TPT2 has USB port power issue

2013-02-13, 22:52 PM

wrote:
If my theory is correct, then this isn't Lenovo's fault. They've built the TPT2's USB port in full compliance with USB specs. 

 

This is what I think quite a few people here suspect. The problem is that some of the competing Atom devices seem to have allocated more current (beyond USB2 spec), allowing them to run some of the devices that the TPT2 can't handle.That puts the TPT2 a step behind the competition, but the consumer can only learn about this from this forum and those two reviews. 

 

Even if Lenovo is in their right stating that this device supports USB 2 compliant devices, it would be helpful to consumers if they stated that "bus powered devices are supported up to 2.5W" or whatever the number is. That's a positive statement that would still inform customers.

 

Either way, as I've said before, assuming that this interpretation is correct it's still a fine device, but they may get quite a few returns as 'uninformed / unreasonably demanding customers' are finding out some of their USB devices won't power up. 

 

Still hoping for an official Lenovo response on this. 

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4036 Posts

12-22-2008

Canada

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Re: TPT2 has USB port power issue

2013-02-14, 0:42 AM

joesixgig wrote:

Even if Lenovo is in their right stating that this device supports USB 2 compliant devices, it would be helpful to consumers if they stated that "bus powered devices are supported up to 2.5W" or whatever the number is. That's a positive statement that would still inform customers.


It sems to me that wouldn't be very informative at all because few people know how much power their external HDD/DVD draws. Besides that reads like some sort of limitation on Lenovo's part when in fact their USB port fully conforms with the standard.
A better warning might be something like, "One powered USB port. Note some USB devices like external hard disks and DVD recorders may require additional power."

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50 Posts

02-14-2013

United States, Dayton Ohio

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Re: TPT2 has USB port power issue

2013-02-14, 1:58 AM

I guess I'll add myself to the long list of owners who can't use their external hard drives.  Luckily I hardly ever use them anyway... If any of you have a large cloud storage account you could put your files in there and download them to the tablet.  That's not supposed to be a solution of course, just what I plan on doing for now. 

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135 Posts

01-19-2013

Austria

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Re: TPT2 has USB port power issue

2013-02-14, 9:26 AM

wrote:
[...]
It would be interesting to see how much current the typical external HDD/DVD devices draw from the USB port. Perhaps someone with ammeter and a spare USB cable that they can hack, will do some measurements on both a TPT2 and other ThinkPads that have multiple USB ports.

Have a look at post #108 and #133 in this thread.

 

 


 

wrote:

[...] 'uninformed / unreasonably demanding customers' [...]

 

 


 

Judging others based on hearsay?

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