USB receptacles

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malachi constant

Senior Member
Location
Minneapolis
We (consulting engineers) are increasingly being asked to specify USB outlets in common area spaces - lobbies, libraries, etc. No problem, right?

Something struck me today though. I rented a car a few months ago and as it had integral USB ports I left my car charging adapter at home. Unfortunately I found that USBs in "older model" cars (like, a couple years old) aren't always compatible when it comes to charging your iPhone. So pretty soon I had to pull over and by a charging adapter. I looked it up when I got home and found out this is a thing - newer phones don't always charge on older car USBs.

That made me think, are our clients going to be swapping out USB outlets in their lobbies every five years (seven years? two years?) because new phones aren't backwards compatible with older USBs? I've never had the problem on a computer or wall charging USB outlet. It seems like such a ubiquitous standard - I would be surprised if it wasn't still working in five years.

It is probably a good use of money to put in the USB outlets now, even with a decent chance of having to replace them en masse in 5+ years. They aren't that expensive or difficult to swap out. But thought I would pose the question to this community and see what you guys think. Thanks!
 

GoldDigger

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Location
Placerville, CA, USA
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Retired PV System Designer
Current standards have extended the maximum current available from USB from the original 500ma to 2.1A or more IF the source and the device follow a handshake standard.
Many high power devices, like tablets, will not even try to charge from a 500ma limited source. And older charging cords (especially long or retractable) have too high a VD to support high current devices.
It is a jungle, but current new sources with 2.1A capability should be good for a long time.
 

Pharon

Senior Member
Location
MA
I hate the entire concept of USB outlets. What an utter waste of a power receptacle space. Why would people want to limit themselves to only being able to use it for one single purpose?

It's like having a special receptacle JUST for toasters.
 

dfmischler

Senior Member
Location
Western NY
Occupation
Facilities Manager
I think USB outlets are a bad idea in general, particularly now that some of the USB security issues have come to light. Nobody should be encouraging average folks to charge their mobile devices using ports that they do not control (how do you *know* that it is just a charging port and that it will not suck your phone's data dry, resulting in identity theft and social media blitzkrieg).
 
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iwire

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Location
Massachusetts
I think USB outlets are a bad idea in general, particularly now that some of the USB security issues have come to light. Nobody should be encouraging average folks to charge their mobile devices using ports that they do not control (how do you *know* that it is just a charging port and that it will not suck your phone's data dry, resulting in identity theft and social media blitzkrieg).

You don't see that as a personal choice type of thing?
 

GoldDigger

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Location
Placerville, CA, USA
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Retired PV System Designer
I hate the entire concept of USB outlets. What an utter waste of a power receptacle space. Why would people want to limit themselves to only being able to use it for one single purpose?

It's like having a special receptacle JUST for toasters.
Which is why the good ones are also either single or duplex outlets.
The hassle of individual adapters moving around and getting lost makes a clean wall receptacle very attractive to me. It also gives me a high power one or two outlet USB that is likely (fingers crossed) to be more reliable than the average off the shelf adapter?
 

malachi constant

Senior Member
Location
Minneapolis
bingo

bingo

We spec a duplex outlet with two USB ports. Cooper TR7746 or equal. And as a user I can attest it is much more convenient to only carry a cord, as opposed to a cord and adapter. As our USBs are typically going into schools or other public institutions I'm much less concerned about people thinking they are "unsafe" - but we may consider marking them somehow. Any suggestions?

All things considered I feel like it is a good design, especially when the Owner is requesting it. Thanks for the input!
 

wptski

Senior Member
Location
Warren, MI
Current standards have extended the maximum current available from USB from the original 500ma to 2.1A or more IF the source and the device follow a handshake standard.
Many high power devices, like tablets, will not even try to charge from a 500ma limited source. And older charging cords (especially long or retractable) have too high a VD to support high current devices.
It is a jungle, but current new sources with 2.1A capability should be good for a long time.
That's USB 3.1 announced in July 2013 but no PC with that new port on the market yet.
 
security

security

I think it will be awhile - it's really fast - some information on the new standard.

http://www.tomshardware.com/news/usb-3.1-usb-type-c-connector,27796.html

BTW - your phone can get hacked - it's called Juice-Hacking - by means of a USB power outlet.

http://krebsonsecurity.com/2011/08/beware-of-juice-jacking/

I work for a large bank and we are doing a pilot program where we are adding them to cubes and offices so people will not be plugging there phones into the computers to charge due to the security risk of viruses on phones infecting bank network. Good selling point you can use
 

wptski

Senior Member
Location
Warren, MI
I work for a large bank and we are doing a pilot program where we are adding them to cubes and offices so people will not be plugging there phones into the computers to charge due to the security risk of viruses on phones infecting bank network. Good selling point you can use
You can blame that on the phone manufactures. There are USB cords with no data pins connected for charging "only" but because of the phones, they won't charge. There are tablets with a second port that one can charge from with no data connection. They can make them data safe but they just don't.
 

Aleman

Senior Member
Location
Southern Ca, USA
I think USB outlets are a bad idea in general, particularly now that some of the USB security issues have come to light. Nobody should be encouraging average folks to charge their mobile devices using ports that they do not control (how do you *know* that it is just a charging port and that it will not suck your phone's data dry, resulting in identity theft and social media blitzkrieg).

Man, I thought I was paranoid:p. I think the juice hacking thing refers to USB ports on machines that are hooked to networks. If they can hack a phone over my house electrical service...well then it's all over.
Gonna buy more guns and food.
 

dfmischler

Senior Member
Location
Western NY
Occupation
Facilities Manager
I think the juice hacking thing refers to USB ports on machines that are hooked to networks. If they can hack a phone over my house electrical service...well then it's all over.
I would think this is mostly a concern in public/corporate/government buildings or air/train/bus transportation where it is in somebody's interest to swap out the wall-mounted (or seat-mounted) charging port for a networked port when nobody is looking. Kinda like throwing a baited hook in the water: you never know who you'll get. I'm pretty sure that if this hasn't happened yet, it will. I think that unless you are already on somebody big's radar you have nothing to worry about in your home.

There has been speculation that the whole StuxNet attack started with somebody picking up a USB flash drive in a parking lot and sticking it in their computer to see what was on it.
 
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FionaZuppa

Senior Member
Location
AZ
Occupation
Part Time Electrician (semi retired, old) - EE retired.
I hate the entire concept of USB outlets. What an utter waste of a power receptacle space. Why would people want to limit themselves to only being able to use it for one single purpose?

It's like having a special receptacle JUST for toasters.

what wasted space?
t5832-w.jpg


Man, I thought I was paranoid:p. I think the juice hacking thing refers to USB ports on machines that are hooked to networks. If they can hack a phone over my house electrical service...well then it's all over.
Gonna buy more guns and food.

the data pins are usually not connected, the outlets dont have the comm chipsets in them, just a diode bridge, small xformer, cap.coil for noise, likely auto-reset fuse, and 5v regulator.

if the device needs comms to get charge then perhaps we consumers should demand the makers of such devices to stop being stupid, a 5v supply on pins 1 & 4 is all that should be needed to allow a device to charge.
 
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GoldDigger

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Location
Placerville, CA, USA
Occupation
Retired PV System Designer
The part of the USB spec that allows the charging source to supply more than the USB 1.0 maximum current specifies either passive signaling or an active data handshake using the data pins, even with a "charge only" cable.
 

FionaZuppa

Senior Member
Location
AZ
Occupation
Part Time Electrician (semi retired, old) - EE retired.
The part of the USB spec that allows the charging source to supply more than the USB 1.0 maximum current specifies either passive signaling or an active data handshake using the data pins, even with a "charge only" cable.

some devices look for voltage across D+ and D- to allow charging at all. its very silly. simply put current clamp in the power supply, have at it, you wont get more than the current clamp, etc.

and then there's this which will have USB charger folks scrambling.

In July 2012, the USB Promoters Group announced the finalization of the USB Power Delivery ("PD") specification, an extension that specifies using certified "PD aware" USB cables with standard USB type A and B connectors to deliver up to 100 W of power at 20 V. For a PD-aware cable with a Micro-USB connector the maximum power supported is up to 60 W at 20 V, 36 W at 12 V and 10 W at 5 V. In all cases, both host-to-device and device-to-host configurations are supported.[104]

The intent is to permit uniformly charging laptops, tablets, USB-powered disks and similarly higher power consumer electronics, as a natural extension of existing European and Chinese mobile telephone charging standards. This may also affect the way electric power used for small devices is transmitted and used in both residential and public buildings.
 

FionaZuppa

Senior Member
Location
AZ
Occupation
Part Time Electrician (semi retired, old) - EE retired.
That outlet costs more than two times what one of these costs, just FYI:

cost? nobody said cost yet, what was said was "wasted space".

Leviton has two USB dual outlet w/ 3.6amp USB

Duplex Receptacle - Currently is the highest charging device on the market with 3.6 Amps of charging power. This flagship addition to Leviton line of USB Charger Devices has the capability to charge two USB powered electronic devices utilizing its two USB Ports, leaving the two Tamper-Resistant Receptacles free for other uses.
 
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