Incompatible Self-Powered Hub

Just for fun, I looked for the USB certification mark on this hub.  The hardware doesn't have one.  That's not uncommon of course, but the point is that the hardware isn't lying about compliance.

For even more fun, I checked the packaging which by some miracle hadn't been thrown out yet, and discovered two interesting things:

• The packaging not only carries a Certified USB Hi-Speed mark, but also proudly proclaims "USB2.0 and USB1.1 Compliant and USB-IF certified" ("USB-IF" is the USB Implementers Forum).
• The packaging has a "2A" legend next to the power supply symbol, despite the fact that the hub's mains adapter is marked "MODEL: YD-001 OUTPUT: 5V 1000mA".

So, my guess is that Dynamode bought in a bulk load of uncertified hubs of unknown compliance, didn't bother to check whether they were USB2.0 compliant or not, bundled them with a random mains adapter, and their marketing division made up fictional packaging without reference to what was actually being provided.  And Farnell buyers fell for the false advertising by Dynamode.

It's a funny old world.

Farnell Purchasing Dept --- please give Dynamode a heap of pain, plus added ridicule for incompetence.

Morgaine.

Morgaine Dinova wrote:

 

For even more fun, I checked the packaging which by some miracle hadn't been thrown out yet, and discovered two interesting things:

 

• The packaging has a "2A" legend next to the power supply symbol, despite the fact that the hub's mains adapter is marked "MODEL: YD-001 OUTPUT: 5V 1000mA".

 

I decided to have some fun too and see what the USB 2.0 spec has to say about how much current a self-powered hub should supply:

Section 7.2.1:

 

Self-powered hubs: ... Hubs that obtain operating power externally (from the USB) must supply five unit loads [500 mA] to each port. Battery-powered hubs may supply either one or five unit loads per port.

So  a 4-port hub needs 2A and a 7-port hub 3.5A to comply.  The adapter obviously didn't read the spec.

And people think engineers don't have fun!

John Beetem wrote:

 

So  a 4-port hub needs 2A and a 7-port hub 3.5A to comply.

Belkin get a lot of flak for poor quality hardware (mostly deserved, from my own experience), but interestingly their own 7-port hub model FSU307 has a 3.8A mains adapter, does not feed +5V upstream through the A-B lead, and works fine as a downstream self-powered hub for Pi.

What's more, despite supplying only 5.05V out open-circuit, it can power the Pi perfectly through an A to micro-USB lead, and a fairly high-resistance one at that (100mV drop when Pi is quiescent).  So, kudos to Belkin there.  However, that hub cost more than the Pi !!!

Unfortunately I have to put the Belkin back where it was after this test as its beefy power was needed there, but it provided useful comparison.  I don't need high power for the Pi's hub, just USB compliance and Pi compatibility, which the Dynamode lacks.

Morgaine.

Funny enough, i'm not completely surprised by the lack of compliance of the Dynamode kit, they are not exactly a top tier manufacturer are they ?

It is cheap and i'm afraid that this only confirms that you get what you pay for !

Steve

Steve Read wrote:

 

Funny enough, i'm not completely surprised by the lack of compliance of the Dynamode kit, they are not exactly a top tier manufacturer are they ?

Well perhaps this varies by country, but at least in the UK, the fact that a company is not "top tier" does not give it a free pass to make false claims about standards compliance nor about power rating of their enclosed mains adapters.  They have the same duty as everyone else.

UK consumer laws make the buck stop with the retailer, Farnell in this case, and Farnell is definitely a "top tier" company.  It's unfortunate that they were deceived by a poor quality outfit like Dynamode, but now that they know about it, they in turn have a duty to prevent further customers from being deceived by the false advertising.

I don't know how things work behind the scenes in this sector, nor how companies sort out these kinds of mishaps among themselves, but I expect that Dynamode is about to get an unhappy phone call from an irate corporate buyer.  I certainly don't expect Farnell to collude with them and hide the problem.  Their "Best of British" tag would go down the drain pretty fast if they did that.

We'll see what happens.  Keep your eye on the Pi Accessories page.

Morgaine.

Completely agree that Farnell is a *great* British company, no argument there from me !

I guess they can't possibly fully test every bit of kit they hold (Don't they carry 100K + lines?) so it is only down to situations like this that can them aware.

In other news, i've just bought a Gertboard, so they have a bit more of my cash !

Don't they carry 100K + lines?

http://uk.farnell.com/jsp/bespoke/bespoke4.jsp?bespokepage=farnell/en_UK/support/about.jsp

"with fast, easy access to over 480,000 stocked products" - it's hard to imagine the scale of keeping track of that many products.

In other news, i've just bought a Gertboard, so they have a bit more of my cash !

I see they're not showing a lead time on it, what sort of estimated delivery date did they give you ?

Nearly Half a million lines, can't even comprehend that !

Estimated delivery date of w/c 8th October for the Gertboard.

*sigh at the lead-times* It's like the RPi launch all over again...

Hopefully it improves, I've just noticed the front page here says "Shipping begins mid-September". I suppose it'll be the PCB lead times that control it, the rest of the parts look to be fairly standard stuff that you'd expect to have off-the-shelf availability.