USB not delivering power - T42p

T4x series specific matters only
Post Reply
Message
Author
shadow99
Posts: 1
Joined: Tue Apr 04, 2006 10:14 am

USB not delivering power - T42p

#1 Post by shadow99 » Tue Apr 04, 2006 10:17 am

New t42p. USB 2.0 drivers all installed. USB ports are working fine, but I used to charge my cell phone on the road via USB on a T30. These ports arent delivering power. Is there something I need to do??

bill bolton
Admin
Admin
Posts: 3848
Joined: Thu Sep 01, 2005 10:09 am
Location: Sydney, Australia - Best Address on Earth!

Re: USB not delivering power - T42p

#2 Post by bill bolton » Tue Apr 04, 2006 11:05 pm

shadow99 wrote:but I used to charge my cell phone on the road via USB on a T30. These ports arent delivering power. Is there something I need to do??
Whether or not it used to work on a T30 is no indication that it should have worked. The USB 2.0 spec requires that a USB device negotiates the power level with the port.

The USB ports on current ThinkPad models adhere to that energy managmenet aspect of the USB 2.0 specification and unless your phone is a full USB device, its likely the port controller will not even attempt to deliver anything other than the minimal specified un-negotiated energy level to a device that does not negotiate its energy needs.

Cheers,

Bill

Post Reply
  • Similar Topics
    Replies
    Views
    Last post

Return to “ThinkPad T4x Series”

Who is online

Users browsing this forum: No registered users and 38 guests