USB acts different between routers

Do you think you can send me such a device for troubleshooting?

It’s all of the mt300n v2. I have over 80 of them, not one of them recognizes this device while the ar300’s all do.

I mean “this device”.

Sorry, I meant to come back all day to edit that but kept getting busy.
The devices are over $100 each so I’m not sure I want to ship one to China I assume.
However, I could give you remote access to a v2 with the device connected if that would help?

So other than what I’ve done, what else could I try to find out what is causing this?
I would prefer using just one model if possible.

Can you check the results of the power draw via a DMM or similar device? I suspect the Mango may not be pushing a full 5V/500mA.

Perhaps a powered USB hub could be put in place.


Using a similar meter as yours;
Without the USB stick connected, I see 5.18V, 0.17Amps.
With it connected, it’s 5.17v at 0.19Amps

I’m not sure that’s the problem since the device isn’t even being seen. You’d think it would be seen or there would be something in the log, even if just for a few seconds.

I tried a powered hub and no difference.

(I should point out I just pulled that image fr a search. I don’t have one… so I’m pretty useless here re: logs.)

NP, but still have no leads on why this is happening. Would be nice if a gl.inet person could offer some thoughts on testing.

Well, @alzhao is the CTO; I think he’s interested in getting the router in his hands but I don’t want to put words in his mouth.

I think he wanted one of the USB devices, not the router?

I tried a USB device using cp210x chipset and Mango can see it.

I also tried other two USB devices which usb serial chipset and the USB can also detect.

Maybe you can send me one device and after troubleshooting I can send you back.

You were right bring.fringe18.

I purchased another powered hub of better quality and now the mango can see the usb device. However, the problem is the mango because I’m providing it power from a PoE connection so that it can draw what ever it needs but it’s not doing it.

1 Like

That reads as if you’ve discovered a bug to kick over/up to GL to straighten out.

(I look forward to you marking my post ‘solved.’ What can I say? I’m a little egotistical. :wink: Have a good one.)

Well, it was the answer but it’s not actually the solution :).
There is a problem with the USB port of this device and I don’t know what the solution will end up being as I cannot add powered hubs to every Mango router.

1 Like

Perhaps not but now it’s on GL to investigate further why their device isn’t pushing a full 500mA. Maybe there’s something needing to be tweaked in the custom build of OpenWrt they’re working with.

It may be this reason or may be not.

Even there is not enough power there will be log in kernel showing some error -71 etc.

I was asking when I started the post, how can I diagnose this then?
Is there a way to log this information?

For this diagnosis you need some measuring/testing equipment.
A USB 2.0 has to be able to deliver a voltage between 4.75V and 5.25V with a current of 0.5A (former 0.1A). The first thing I would do, is to connect a load (10 Ohm, 5W) and measure the voltage. It should be clearly above 4.75V.
The second measurement is the current consumption of the device, this is not as easy as it seems. You can measure the current using a device as shown above but this don’t tell you anything about peak-currents occurring e.g. during plug-in or switch-on. You have to do these measurements using an oscilloscope to determine the peak-currents and see, if they exeed the specification of USB2.0.
Additionally you have to measure the voltage with an oscilloscope to show, that it stays within the specification all the time.
To find a solution, you first have to know what the problem is.

1 Like

… or you could just grab the spec sheet & hope the manufacturer’s not lying. YMMV.

1 Like