Does Sleep mode shut off power to ports?

Hey guys. I have recently bought a bus powered firewire 400 audio interface (Focusrite Safire 14). I am connecting it to my 2014 MBP 15" using a Thunderbolt adapter. I learned once I had bought the interface that firewire is not hot-pluggable and therefore i will possibly have to shut down my mac each time I want to connect/disconnect the devise which is not convenient.

I was just wondering;

1. Does putting mac to sleep shut down all the power to the TB ports? (all the lights on my interface switch off but is there still power being supplied to it?!)
2. Is there any other way to force shut down the Thunderbold ports on a mac (for instance by using Terminal)?

Ps, This article doesn't seem to mention anything about the state of Thunderbolt or Firewire ports during Sleep mode;
https://support.apple.com/en-gb/HT201714

I read your other post so I understand your problem.

I can only answer Q1. In every iMac I've ever had, putting the Mac to sleep cut the power to the USB ports. Whether this can be overcome or modified by Terminal or other methods, I know not. I have never had the courage to meddle with Terminal; but the many senior members who use it on a daily basis may advise accordingly.

Ian

Josh

My post was just behind your second one. Having read the article you linked, it would appear to support my experience when it says

"The USB ports only responds to the power key on an external keyboard "

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Ian

Firewire is designed to be hot-plugged, but looks like a bunch of people are blaming others (rather than their designs) for any failures that might occur with hot-plugging.

Anyway, when the system goes to sleep, all ports lose their power as well..

Can't help with TB but USB keeps charging my Kindle when asleep.

Wanted to mention that on my 2011 MBP my Garmin GPS watch still charges via USB when the computer is "sleeping".

- Nick

Hey guys. There seem to be a few different opinions coming up on this post. Regarding you comments on experience with USB; am I meant to take it that if USB continues to charge a kindle whilst mac is asleep, so will the TB ports continue to provide power? Or might power be shut down from the different types of ports, independently? (eg power withheld from usb but NOT from TB)

Are there any tests I might be able to do to check whether there is definitely any power running through the TB cable once the mac is asleep? (maybe by testing an exposed part of the cable connector using a voltage detector?COLT® AC Voltage Detector 90V~1000V Tester Pen Stick Probe: Amazon.co.uk: DIY & Tools

Alternatively, do you think I might be able to get a conclusive answer from apple support or from a genius on this matter?

JoshJ said:

Are there any tests I might be able to do to check whether there is definitely any power running through the TB cable once the mac is asleep?

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As I mentioned in my earlier post. The USB ports on my 2011 MBP seem to still be powered while it is sleeping since it continues to charge my Garmin GPS watch. Most devices that we folks us that need power (or need a battery recharged) generally use the USB port for this.

So my question back to you is…do you have a Thunderbolt device that needs power when the computer is sleeping? And if it does. Why not simply plug that device into your MacBook Pro…put the MacBook Pro to sleep…and see if the device remains powered?

- Nick

Ps; this non-contact voltage pen detects from 90V to 1000V AC. Would this work for testing the cable/the interface for power?

http://www.amazon.co.uk/dp/B00AXN6IPU/

pigoo3 said:

As I mentioned in my earlier post. The USB ports on my 2011 MBP seem to still be powered while it is sleeping since it continues to charge my Garmin GPS watch. Most devices that we folks us that need power (or need a battery recharged) generally use the USB port for this.

So my question back to you is…do you have a Thunderbolt device that needs power when the computer is sleeping? And if it does. Why not simply plug that device into your MacBook Pro…put the MacBook Pro to sleep…and see if the device remains powered?

- Nick

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Thanks Nick. i am just wondering whether the USB ports work in exactly the same way as the TB ports in terms on power supply when in sleep mode. Unfortunately I do not have an external device that I can test charge that is TB connectable, only USB.

JoshJ said:

i am just wondering whether the USB ports work in exactly the same way as the TB ports in terms on power supply when in sleep mode.

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At least with my setup...I think that I already answered that twice. Maybe what I quoted above was written in reverse. Maybe what you meant to say was this:

"i am just wondering whether the TB ports work in exactly the same way as the USB ports in terms on power supply when in sleep mode."

JoshJ said:

Unfortunately I do not have an external device that I can test charge that is TB connectable, only USB.

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If this is the case...are we having a theoretical discussion?

- Nick

By the way. Here's an Apple Support document that has quite a bit of info regarding Thunderbolt ports. Unfortunately (as far as I could find)…it does not say anything about the TB ports staying powered while the computer is sleeping:

https://support.apple.com/en-us/HT204154

- Nick

JoshJ said:

Alternatively, do you think I might be able to get a conclusive answer from apple support or from a genius on this matter?

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It's very possible they may ask you to describe your specific situation…and what you're trying to do/accomplish. If a theoretical question…it may be more difficult to get an answer.

For example. Do any Thunderbolt devices exist that would need TB port power while the computer is "sleeping"?

Or…if the TB port does stay powered when the computer is asleep. Why would someone want to charge their iPad, iPhone, iWatch (or any other device that needs charging) via the Thunderbolt port…when it's very easy (and probably less expensive) to do it via the USB port?

The bottom line is. What Thunderbolt device do you want to use…that would need TB port power when the computer is sleeping??

- Nick

pigoo3 said:

It's very possible they may ask you to describe your specific situation…and what you're trying to do/accomplish. If a theoretical question…it may be more difficult to get an answer.

For example. Do any Thunderbolt devices exist that would need TB port power while the computer is "sleeping"?

Or…if the TB port does stay powered when the computer is asleep. Why would someone want to charge their iPad, iPhone, iWatch (or any other device that needs charging) via the Thunderbolt port…when it's very easy (and probably less expensive) to do it via the USB port?

The bottom line is. What Thunderbolt device do you want to use…that would need TB port power when the computer is sleeping??

- Nick

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Hi Nick. Thanks a lot for your replies. I think I may not have stated my OP clearly enough;

The reason I am asking whether a (bus powered) FW device (using a TB adapter) is hot pluggable whilst in Sleep mode is simply because I have read that it is possible to damage the posts on either end of the chain by doing so (frying either the FW 400 port on the audio interface or the TB ports on my mac).
I obviously want to avoid this but completely shutting my mac down each time I want to connect/disconnect the interface is very inconvenient & creates a workflow issue.


Just wanted to update this thread as I have been playing around with the interface a bit more this week;

I have noticed that the interface does have a "Power" light on it along with a "FW" (firewire) & "LKD" (locked) light.
When I put the mac to sleep all 3 lights switch off after about 15 seconds. However, when I plug the interface back in again (with mac still supposedly in sleep mode) the lights all light up.

Does this mean that power is still being supplied to the TB ports whilst in Sleep mode? Or, is it that plugging something into the TB ports wakes the system & starts it supplying power to the ports?

Does this mean that power is still being supplied to the TB ports whilst in Sleep mode? Or, is it that plugging something into the TB ports wakes the system & starts it supplying power to the ports?

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The latter in my view. What you elegantly describe:

When I put the mac to sleep all 3 lights switch off after about 15 seconds. However, when I plug the interface back in again (with mac still supposedly in sleep mode) the lights all light up.

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suggests to me that all ports shut down and that it is the reconnection which reawakens the system.

Can't prove my theory, but it appears logical from what you have stated.

Ian

Josh J - Not sure if you got an answer on the voltage question so here goes. The 90--1000 volt pen is for detecting AC voltage of at least 90V. It is basically an AC light bulb that lights up and is used for detecting household (normally) outlet power. The USB ports are DC voltage and in the 5 Volt range. If you have a voltmeter you could measure across the USB or thunderbolt terminals (tricky). Easiest to just plug something in and see if the something is getting charged.