USB hubs are a thing I prefer to stock on, since I really often use these in my projects . Threrefore, just when I was running low on ’em, I ordered a bunch in bulk from china. Took about a month, till our slowpoke-post delivered those.
Anyway, being pessimisticby default, I started by doing an lsusb -vv on the hub device:
lsusb -vv -s 7:11 Bus 007 Device 011: ID 0a05:7211 Device Descriptor: bLength 18 bDescriptorType 1 bcdUSB 2.00 bDeviceClass 9 Hub bDeviceSubClass 0 Unused bDeviceProtocol 0 Full speed (or root) hub bMaxPacketSize0 8 idVendor 0x0a05 idProduct 0x7211 bcdDevice 1.00 iManufacturer 0 iProduct 1 USB2.0 HUB iSerial 0 bNumConfigurations 1 Configuration Descriptor: bLength 9 bDescriptorType 2 wTotalLength 25 bNumInterfaces 1 bConfigurationValue 1 iConfiguration 0 bmAttributes 0xe0 Self Powered Remote Wakeup MaxPower 100mA Interface Descriptor: bLength 9 bDescriptorType 4 bInterfaceNumber 0 bAlternateSetting 0 bNumEndpoints 1 bInterfaceClass 9 Hub bInterfaceSubClass 0 Unused bInterfaceProtocol 0 Full speed (or root) hub iInterface 0 Endpoint Descriptor: bLength 7 bDescriptorType 5 bEndpointAddress 0x81 EP 1 IN bmAttributes 3 Transfer Type Interrupt Synch Type None Usage Type Data wMaxPacketSize 0x0001 1x 1 bytes bInterval 255 Hub Descriptor: bLength 9 bDescriptorType 41 nNbrPorts 4 wHubCharacteristic 0x0009 Per-port power switching Per-port overcurrent protection bPwrOn2PwrGood 50 * 2 milli seconds bHubContrCurrent 100 milli Ampere DeviceRemovable 0x00 PortPwrCtrlMask 0xff Hub Port Status: Port 1: 0000.0100 power Port 2: 0000.0100 power Port 3: 0000.0100 power Port 4: 0000.0100 power Device Status: 0x0001 Self Powered
Okay, now let’s make sense out of it. First, the line marked red tells us this is no way a high speed (480 mbit/s) hub, as the seller said, but a full-speed one (12 mbit/s). Some people call these 1.1 hub for some reason, although this is not correct.
Next is the line I marked purple. It is the only string descriptor, and it is displayed by windoze whenever this hub is plugged in. Enough to confuse some users.
Heh, good I needed those for a few hobby projects, and not a business prototype ™. Otherwise the deadline would have been screwed up (Or I had to make a run to a local store).
Anyway, I opened the dispute, got the money back, and the hubs were also remained in my hands. Epic win. Time to crack them open and see what’s inside.
Inside looked awful.
A few dry facts come along:
- No capacitor mounted on the +5V power line. Problems may and will arise
- Side ‘leafs’ if usb connectors are not soldered at all. These will fall off in a week or so
- “Per-port power switching” & “Per-port overcurrent protection” that are advertised in descriptor are bullshit.
To fix these bugs, I added a 220uF capacitor to the power line and soldered all the connectors properly. Took me about a minute or so.
Regarding the dispute, I can say that I was lucky. The seller didn’t want to risk undergoing the whole process, and I got my money back fast.
But just in case, I’ll leave some useful info.
Our only weapon here – “usb specs”. As they said in some nvidia presentation “reading specs can make you more powerful, than you can possibly imagine”.
The hub IS a 2.0 hub, so never state it is a 1.1 hub. It is not a ‘high speed’, but a ‘full speed’.
Some sellers might state that this is a ‘high speed’ hub, but write “badwidth: 12mbit/s” somewhere in fine print. This should be enough for a dispute. However, if they state that it is full-speed hub, there’s no way one can win the dispute – the description is correct.
I have just received some fakes from Ebay.
Here’s part of my report through Ebay:
“These items are fake USB2 devices. I have run USBlyser software on these and they confirm as USB1. Also tested throughput and confirm these are FULL speed (11Mb) devices and not Hi-Speed as advertised. I would like a refund on these items and would like to return them but not at my cost. The seller should cover the cost of the return as they have blatantly broken rules and sold counterfeit products. This has been reported to Ebay. Software reports: https://dl.dropboxusercontent.com/u/124161/FakeUSB/1.png https://dl.dropboxusercontent.com/u/124161/FakeUSB/2.png https://dl.dropboxusercontent.com/u/124161/FakeUSB/3.png https://dl.dropboxusercontent.com/u/124161/FakeUSB/4.png https://dl.dropboxusercontent.com/u/124161/FakeUSB/without-hub1-w-
rite.png https://dl.dropboxusercontent.com/u/124161/FakeUSB/without-hub2-r-
ead.png
https://dl.dropboxusercontent.com/u/124161/FakeUSB/fake-item.png “
In my experience, it seems that every cheap item from China on eBay is fake, counterfeit, trash. I no longer hold out any hope of ever getting a good deal.
The only value that China has on eBay is as a source of free electronic parts. First ask the seller if it is real, if they say yes, then buy the item, then if it ever arrives, IMMEDIATELY test it (they usually send it as late as possible in the hopes that you will miss the deadline for a return), then get a refund and use it for parts.
Or just skip the hassle and risk and just buy something for full price in a store. In this case, the prices really are too good to be true; apparently there is no such thing as a good deal, at least not from China.
The hub IC in these with VID:PID 0a05:7211 is the Micov MW7211, and it is a USB 2.0 Full Speed hub.
Datasheet can be found here: http://web.archive.org/web/20170613120608/http://www.usbdev.ru/?wpfb_dl=2700