Which powered USB hub is good and safe?

[Joerg]

Hello Folks,

Just ordered a USB spectrum analyzer (SignalHound), track gen, and
stuff. These draw close to the half amp that a USB port allows, each,
and with all the other stuff I have that now calls for a powered USB
hub. So ...

Which ones are good and safe? Or which brands in general? Meaning a very
low chance of some regulator popping a gasket and frying all the
connected stuff. Metal enclosure, power switch and height under 2-1/4"
would also be nice.

Example:

http://www.walmart.com/ip/Gear-Head...Saving-Switch-Black/16451759?findingMethod=rr

No idea why the power switch is where the cables come off, makes no
sense. And I don't know most of the brands which is why I am asking.

 

[Martin Riddle]

Hello Folks,

Just ordered a USB spectrum analyzer (SignalHound), track gen, and
stuff. These draw close to the half amp that a USB port allows, each,
and with all the other stuff I have that now calls for a powered USB
hub. So ...

Which ones are good and safe? Or which brands in general? Meaning a
very
low chance of some regulator popping a gasket and frying all the
connected stuff. Metal enclosure, power switch and height under 2-1/4"
would also be nice.

Example:

http://www.walmart.com/ip/Gear-Head...Saving-Switch-Black/16451759?findingMethod=rr

No idea why the power switch is where the cables come off, makes no
sense. And I don't know most of the brands which is why I am asking.

I've used the Belkin hubs with out any problems.
<http://www.walmart.com/ip/Belkin-4-Port-USB-Plus-Hub-White/5723577>

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

Cheers

 

[Spehro Pefhany]

Hello Folks,

Just ordered a USB spectrum analyzer (SignalHound), track gen, and
stuff. These draw close to the half amp that a USB port allows, each,
and with all the other stuff I have that now calls for a powered USB
hub. So ...

Which ones are good and safe? Or which brands in general? Meaning a very
low chance of some regulator popping a gasket and frying all the
connected stuff. Metal enclosure, power switch and height under 2-1/4"
would also be nice.

Example:

http://www.walmart.com/ip/Gear-Head...Saving-Switch-Black/16451759?findingMethod=rr

No idea why the power switch is where the cables come off, makes no
sense. And I don't know most of the brands which is why I am asking.

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

http://www.bb-elec.com/product.asp?sku=UISOHUB4

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


Best regards,
Spehro Pefhany

 

[Joerg]

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

http://www.bb-elec.com/product.asp?sku=UISOHUB4

$322, yikes!

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

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

 

[Joerg]

I've used the Belkin hubs with out any problems.
<http://www.walmart.com/ip/Belkin-4-Port-USB-Plus-Hub-White/5723577>

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

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.

 

[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".

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 ?

Well, I'll
need three digits there in a few days

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

 

[Joerg]

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 ?

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.

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

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.

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.

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
80's..

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.

Baaske appears to have one:

http://www.baaske.net/usb2_galvanisch_trennen.html?&L=1

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

 

[Nico Coesel]

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
80's..

I just bought the cheapest one with 8 ports:
http://www.sitecom.com/usb-hub/p/723

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

 

[Joerg]

I just bought the cheapest one with 8 ports:
http://www.sitecom.com/usb-hub/p/723

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.

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

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

 

[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.

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.

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.

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.

Baaske appears to have one:

http://www.baaske.net/usb2_galvanisch_trennen.html?&L=1

Goes to fiber and then back, so you can almost connect to the other side
of town.

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

Why should it be so complicated to create a galvanically
isolated interface? I've never found that too tough.

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

 

[Nico Coesel]

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

The casing does have a nice soft touch to it

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.

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.

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

Depends on the amount of traffic. Many years ago I travelled about
600km through the South of France on my bike. No problems with the
traffic. There was some but not much. The whole trick is to be visible
and look carefully whether people have seen you before getting in
front of their car.

 

[Joerg]

The casing does have a nice soft touch to it

Ah, then it must be a good product

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.

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.

Depends on the amount of traffic. Many years ago I travelled about
600km through the South of France on my bike. No problems with the
traffic. There was some but not much. The whole trick is to be visible
and look carefully whether people have seen you before getting in
front of their car.

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

 

[Joerg]

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.

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".

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.

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

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. ;-)

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

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. ;-)

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 <getting goose bumps> or loaded down and voltage mode.

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

 

[Martin Riddle]

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.

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
<http://www.mouser.com/ProductDetail/Keterex/KXUSB-150/?qs=sGAEpiMZZMuos25lhNoLahchgXDNv7iT>

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

handy gadget

Cheers

 

[Spehro Pefhany]

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
<http://www.mouser.com/ProductDetail/Keterex/KXUSB-150/?qs=sGAEpiMZZMuos25lhNoLahchgXDNv7iT>

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

When the prototype is <= 5V only I'm not too worried, but that isn't
always the case.

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

That is handy.

handy gadget

Cheers

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

 

[Joerg]

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
<http://www.mouser.com/ProductDetail/Keterex/KXUSB-150/?qs=sGAEpiMZZMuos25lhNoLahchgXDNv7iT>

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

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