Surprising behavior of Always On USB ports on a ThinkPad laptop
I have a T450 that according to the specs has three USB ports.
One of those ports is Always On USB port, so even if you turn off the computer, but the laptop charger is connected, this port will be working, so that you can for example charge your mobile phone and other devices. That is port no. 5 on the image below.
So theoretically, when my laptop is turned off but still plugged:
- devices connected to port 2 (normal USB) should not be charging
- devices connected to port 5 (always on USB) should be charging
In practice, this is not the case, and it's very surprising:
- my Sony Xperia smartphone behaves as expected: charges on port 5, does not charge on port 2 (and does not charge on the port on the right hand side)
- however, my Lenovo tablet behaves exactly the other way around! Charges on port 2, does not charge on port 5 (and charges on the port on the right hand side)
How could this could possibly be the case?
usb thinkpad
asked May 10 '17 at 18:11
jakub.gjakub.g
3,44722129
add a comment |
I have a T450 that according to the specs has three USB ports.
One of those ports is Always On USB port, so even if you turn off the computer, but the laptop charger is connected, this port will be working, so that you can for example charge your mobile phone and other devices. That is port no. 5 on the image below.
So theoretically, when my laptop is turned off but still plugged:
- devices connected to port 2 (normal USB) should not be charging
- devices connected to port 5 (always on USB) should be charging
In practice, this is not the case, and it's very surprising:
- my Sony Xperia smartphone behaves as expected: charges on port 5, does not charge on port 2 (and does not charge on the port on the right hand side)
- however, my Lenovo tablet behaves exactly the other way around! Charges on port 2, does not charge on port 5 (and charges on the port on the right hand side)
How could this could possibly be the case?
usb thinkpad
asked May 10 '17 at 18:11
jakub.gjakub.g
3,44722129
add a comment |
I have a T450 that according to the specs has three USB ports.
One of those ports is Always On USB port, so even if you turn off the computer, but the laptop charger is connected, this port will be working, so that you can for example charge your mobile phone and other devices. That is port no. 5 on the image below.
So theoretically, when my laptop is turned off but still plugged:
- devices connected to port 2 (normal USB) should not be charging
- devices connected to port 5 (always on USB) should be charging
In practice, this is not the case, and it's very surprising:
- my Sony Xperia smartphone behaves as expected: charges on port 5, does not charge on port 2 (and does not charge on the port on the right hand side)
- however, my Lenovo tablet behaves exactly the other way around! Charges on port 2, does not charge on port 5 (and charges on the port on the right hand side)
How could this could possibly be the case?
usb thinkpad
asked May 10 '17 at 18:11
jakub.gjakub.g
3,44722129
I have a T450 that according to the specs has three USB ports.
One of those ports is Always On USB port, so even if you turn off the computer, but the laptop charger is connected, this port will be working, so that you can for example charge your mobile phone and other devices. That is port no. 5 on the image below.
So theoretically, when my laptop is turned off but still plugged:
- devices connected to port 2 (normal USB) should not be charging
- devices connected to port 5 (always on USB) should be charging
In practice, this is not the case, and it's very surprising:
- my Sony Xperia smartphone behaves as expected: charges on port 5, does not charge on port 2 (and does not charge on the port on the right hand side)
- however, my Lenovo tablet behaves exactly the other way around! Charges on port 2, does not charge on port 5 (and charges on the port on the right hand side)
How could this could possibly be the case?
usb thinkpad
usb thinkpad
asked May 10 '17 at 18:11
jakub.gjakub.g
3,44722129
asked May 10 '17 at 18:11
jakub.gjakub.g
3,44722129
edited May 10 '17 at 18:23
jakub.g
asked May 10 '17 at 18:11
jakub.gjakub.g
3,44722129
asked May 10 '17 at 18:11
jakub.gjakub.g
3,44722129
asked May 10 '17 at 18:11
jakub.gjakub.g
3,44722129
3,44722129
add a comment |
add a comment |
1 Answer
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This behavior is very possible when the two ports have different "charging signatures", while the two connected devices have different cohesion to charging signatures.
answered May 11 '17 at 2:33
Ale..chenskiAle..chenski
8,70841731
add a comment |
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1 Answer
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1 Answer
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active
oldest
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active
oldest
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active
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This behavior is very possible when the two ports have different "charging signatures", while the two connected devices have different cohesion to charging signatures.
answered May 11 '17 at 2:33
Ale..chenskiAle..chenski
8,70841731
add a comment |
This behavior is very possible when the two ports have different "charging signatures", while the two connected devices have different cohesion to charging signatures.
answered May 11 '17 at 2:33
Ale..chenskiAle..chenski
8,70841731
add a comment |
This behavior is very possible when the two ports have different "charging signatures", while the two connected devices have different cohesion to charging signatures.
answered May 11 '17 at 2:33
Ale..chenskiAle..chenski
8,70841731
This behavior is very possible when the two ports have different "charging signatures", while the two connected devices have different cohesion to charging signatures.
answered May 11 '17 at 2:33
Ale..chenskiAle..chenski
8,70841731
answered May 11 '17 at 2:33
Ale..chenskiAle..chenski
8,70841731
answered May 11 '17 at 2:33
Ale..chenskiAle..chenski
8,70841731
answered May 11 '17 at 2:33
Ale..chenskiAle..chenski
8,70841731
8,70841731
add a comment |
add a comment |
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