Which powered USB hub is good and safe?

I've used the Belkin hubs with out any problems.

Couldn't vouch for current draw, but they probably all use the same SMC hub chip.

Cheers

If you care about your computer and the data on it, maybe one of these:

A bit more $$, of course, it might be cheaper to use an expendable notebook.

Best regards, Spehro Pefhany

$322, yikes!

About the same as some netbooks, indeed. But the main issue is that they seem to contain dinosaur technology, 12Mbps "high speed". Well, I'll need three digits there in a few days :-)

Thanks, Martin, Belkin is where I have some cables from. Bit more expensive than others but they seem more sturdy. I'll look for one with more ports then, and where they come out the back.

That is called "full speed". 480Mbps is "high speed". Can your new box really talk with "high speed", or does it just claim USB 2.0 ?

Dunno about "dinosaur technology".. I don't think 480Mbps galvanic isolation is particularly easy, even with 2011 technology.

Here's a cheaper way for full speed USB 2.0- buy the eval board for the ADuM4160 and put it in a box. $64 from Avnet. Use with any old powered hub.

I'd be interested to know if there is anything available that actually transparently handles galvanic isolation for true "high speed" 480Mbps USB2.0. Usually I tend towards Ethernet for really high data rates.

Best regards, Spehro Pefhany

I called them about that yesterday and they said that it really needs to be USB2.0 because of the data volume. They said that it'll sputter not just if the USB is too slow but also if the processor is pre-2005 and can't handle the incoming traffic.

I've done it in designs. One galvanic isolation project was capable of slightly over 100Mbps (they didn't need any more) and this was in the early 90's. Still in production.

But in this case I do not need isolated USB. It's a spectrum analyzer, not a scope. So I can use a balun up front when sniffing around in HV stuff.

Unfortunately that has only one USB port. I'd need at least six, preferably more. Gradually my whole lab bench is migrating over to USB except for the stuff I use very rarely and where I do not buy new equipment. Such as the logic analyzer, that one is RS232, it's from the

Baaske appears to have one:

Goes to fiber and then back, so you can almost connect to the other side of town. Why should it be so complicated to create a galvanically isolated interface? I've never found that too tough. Haven't tried to reach much past 100Mbps yet because clients haven't needed more but the waveforms all looked really zippy, transition times of a few nsec. I could have probably gotten it down to under a nsec. I've even shunned opto-links because I couldn't bring myself to spend more than a buck for one :-)

I just bought the cheapest one with 8 ports:

If it breaks it goes into the bin and I'll get on my bike to buy a new one. I can use the exersize :-)

Quote "Luxurious materials and smart looks". Now that instills confidence :-)

But I guess they all use more or less the same chips. I am not concerned about breaking but more about the wallwart and/or regulator to go berserk and ... *PHUT* ... a few thousand bucks of stuff is toast.

Same here. But bicycling is dangerous where we live, no bike paths and no sidewalks.

Yes, (especially) using hardware it's often easy to push data out faster than the recipient can continously accept it. And that's not always (not very often, I'd say) reflected in the published specs. Modern devices, even XX/XXX Mbs types, often go on walkabout for surprisingly long times (milliseconds, or even hundreds of ms), so huge buffers, latencies and jitter enter the equation.

Sure. But USB is troublesome to build TRANSPARENT isolators for. It's a bidirectional bus with no external means of seeing the data direction. It's also 480Mbps if you choose to support "high speed". USB 3.0 is a bit different, I have not looked closely at that yet. Might be easier to deal with it, maybe not.

Interesting, thanks, Joerg. Sounds like there is some demand but few suppliers atm.

That's because it's the easy part. ;-) Transformers, fiber, and radio all work well. Sneakernet (storing it on a 32G USB stick as it is acquired and carrying it from workbench to desk) has potentially >>1 Gbs throughput. ;-)

I did a free air optical implementation a few years ago, which was a probably bit more challenging than doing fiber from scratch, but it works very reliably under tough conditions and does not introduce latencies or jitter, which was very important for the application. Got to use Phil H's publications a bit. ;-)

Best regards, Spehro Pefhany

The casing does have a nice soft touch to it :-)

One leg of the wall-wart is connected to ground (the shell of the connector). I doubt the simple wall wart is beefy enough to do any serious damage. The one that came with my hub is rated 5V 2.5A. Though so far I've only connected the hub to embedded ARM platforms.

Depends on the amount of traffic. Many years ago I travelled about

Ah, then it must be a good product :-)

All it takes is the regulator to go open and suddenly all your connected stuff sees 10V/2.5A or whatever ... *POOF* .. crackle ... pop.

Well, I just ordered the one from my link, mainly because it has a power switch. Nice thing is, Radio Shack offered free shipping to a store and there is one on the way to an Alzheimer's place we often visit. So I can pick it up when it gets there. Like in the old days when stuff was shipped to the trading post at the end of the horse trail.

And hope that the trucker coming up behind you didn't finish that bottle of vin rouge all by himself ...

Nice thing is they also offer a 30-day money back guarantee if for whatever reason I don't like it. However, it's a very small company and an engineer answered the phone. He sure knew that product inside and out.

The other nice thing is that they laid their API and all that open so one can program things "homebrew style".

Some of mine were bidirectional as well but I've never designed any USB isolation stuff.

One jolt of sciatic nerve activity can reduce that to zero GB/sec in a jiffy :-)

Free air is indeed tough. Had a few cases as well but that was not high-speed stuff.

Problem with fast stuff is that anything that could "legally" be used as a TIA realistically pegs out way below a GHz. Beyond that you are at the merci of CFB amps or loaded down and voltage mode.

So ... I just ordered the USB hub from my link. Via Radio Shack, of all places.

The new USB Isolator Chips from Analog are great. We have a Keterex USB isolator and its very robust. Will run you $100 or so from Mouser

The ADuM4160 can even supply power across it's interface.

handy gadget

Cheers

I have one of those, for use with laser driver boards that run off a single negative supply (most diode lasers are common-anode, which is a pain). It works fine for running a uC development system, but I haven't tried it with anything with a fat hose.

Cheers

Phil Hobbs

Excellent. I think I'll order one next time I put in a Mouser order.

When the prototype is The ADuM4160 can even supply power across it's interface.

That is handy.

Pretty reasonable price too.. less than $6 in 100's. It would be nice if the guys trying to sell usb instruments would build it in, and just add $40 or whatever to the price.

Best regards, Spehro Pefhany

Well, for this case I do not need any isolation. But yes, the Keterex looks great.