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Author Topic: USB hubs - does anything like this exist?  (Read 4628 times)

Target

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USB hubs - does anything like this exist?
« on: December 29, 2010, 12:03:49 AM »
sorry about the stupid title, but this seems like a logical piece of hardware but I don't seem to be able to find anything like it

I routinely work remotely using a laptop, however laptops generally don't have anywhere near enough USB ports for all the bit's and pieces I use so I use a hub (OK so far).  Trouble with this setup is that it gets pretty untidy

what I want to be able to do is plug in my keyboard, mouse, printer, USB key, RNA token, phone (modem), and external drive and switch them between the laptop and home PC so I'm wondering if there is a hub (7 ports minimum, preferably 10) that works like a KVM switch, ie where I can switch between 2 different inputs (the laptop or my own PC).

To complicate things further, I use a 2.5" 500G external drive that requires a reasonable power supply (it uses 2 ports on the docking station) so ideally the hub needs to be able to provide sufficient power to run the drive...

this seems like a reasonable piece of hardware (and I'm sure I'm not the only one that's had this experience), but I've googled for this several times and come up dry.  I suppose I'd be prepared to pay a reasonable amount for something that is well regarded (I have tried numerous no-name hubs and there is almost always one or two ports that don't work reliably)

Anyone got any idea's?
 

mwb1100

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Re: USB hubs - does anything like this exist?
« Reply #1 on: December 29, 2010, 01:32:46 AM »
I'm not entirely sure that this device will do what you want, but I think you might want to look at Belkin's OmniView SOHO KVM with Audio, USB and VGA:

  - http://www.belkin.co...ss?Product_Id=160623
Quote
The Switch's built-in 2-port USB device hub lets you connect two additional shared peripherals, eliminating the need to disconnect and reconnect these devices when switching between computers.

Now clearly 2 ports isn't 7 or 10, but I'm thinking that if you got a 7 or 10 port hub (I know there are 7 port hubs, but do they make 10 port hubs?) and plugged your junk (no, not that junk) into that, then daisy-chained the hub to one of the switched USB ports on the KVM it might just work.

It might take a while for all the devices to get recognized as being plugged in when you switch (and I think you'll hear a lot of bing, bloops, and bonks from Windows as it detects the devices), but I don't see why it couldn't work.  As far as I know, the KVM just makes the USB switch process appear as an unplug from the computer you're switching away from and a plug-in on the computer you're switching to.

Deozaan

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Re: USB hubs - does anything like this exist?
« Reply #2 on: December 29, 2010, 02:39:18 AM »
plugged your junk (no, not that junk)

This made me come as close to "LOL"-ing as I dared at this hour (1:38AM) in my apartment (in the room above the apt. manager's baby's bedroom).

Very funny! ;D


4wd

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Re: USB hubs - does anything like this exist?
« Reply #3 on: December 29, 2010, 03:49:42 AM »
It sounds like you want to be able to share USB devices between computers.

Like these, (there's some more on the site):
USB 2.0 2-Port Switch for Sharing Devices
USB 2.0 4-Port Switch for Sharing Devices

You might be able to plug a normal self-powered hub into one of the ports, (I don't see why not), which would increase the number of devices accessible.

Here's one that's close to you, (well Brisbane anyway :) ): USB Sharing Hub
« Last Edit: December 29, 2010, 04:00:25 AM by 4wd »

Target

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Re: USB hubs - does anything like this exist?
« Reply #4 on: December 29, 2010, 05:01:49 PM »
It sounds like you want to be able to share USB devices between computers.

that's exactly what i want to do, but seems like this is a niche market

I don't need (or want) to switch monitors, so a KVM would be a bit over the top (wasted)

there are switches (the first 2 options) that share a single device with multiple PC's, but you still need to daisy chain with a hub (or hubs) if you have multiple devices to share

The lindy link is a possible candidate, but only 4 ports

it seems no one has really made what seems like a logical step to me and built a device with penty of ports that does both

as an aside it occurred to me (about 10 minutes after I posted, DUH!) that someone, somewhere must have already done this so I went looking for a DIY version.  There are a number of references of multiple port hubs being constructed by gutting a bunch of cheap hubs and mounting them all in a single case (basically daisy chaining), and it doesn't seem like much of a stretch to extend this concept to add a switch and 2 inputs...

3 unpowered and 1 powered (with a suitable power supply) would give me 12 ports...hmmm 

4wd

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Re: USB hubs - does anything like this exist?
« Reply #5 on: December 29, 2010, 06:11:13 PM »
as an aside it occurred to me (about 10 minutes after I posted, DUH!) that someone, somewhere must have already done this so I went looking for a DIY version.  There are a number of references of multiple port hubs being constructed by gutting a bunch of cheap hubs and mounting them all in a single case (basically daisy chaining), and it doesn't seem like much of a stretch to extend this concept to add a switch and 2 inputs...

3 unpowered and 1 powered (with a suitable power supply) would give me 12 ports...hmmm  

A simple toggle switch to the control lines of a Quad Bilateral Switch, (4066 CMOS or 74HC(T)4066 TTL), is a relatively simple way to do it and it would be self-powered.  However, I'd look at making all the ports powered via external means.  You're talking about 12 ports, if they are all occupied at a relatively modest power consumption of 100mA, even with 1 powered that's still 1.1A, over twice the specified current sourcing for 1 USB port - which will be where it's coming from.

A more interesting way would be to use a micro-controller, (eg. PIC, Atmel), to monitor the incoming PC USB data lines and through-switch to the devices - more interesting but maybe not more practical since, (as mwb1100 said), Windows would need time to identify all the devices before data could be sent through, so you'd need to incorporate some sort of RAM buffer I'd think or message back to the OS to hold until device ready is signaled.
« Last Edit: December 29, 2010, 06:15:01 PM by 4wd »

Target

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Re: USB hubs - does anything like this exist?
« Reply #6 on: December 29, 2010, 06:25:47 PM »
A simple toggle switch to the control lines of a Quad Bilateral Switch, (4066 CMOS or 74HC(T)4066 TTL), is a relatively simple way to do it and it would be self-powered.  However, I'd look at making all the ports powered via external means.  You're talking about 12 ports, if they are all occupied at a relatively modest power consumption of 100mA, even with 1 powered that's still 1.1A, over twice the specified current sourcing for 1 USB port - which will be where it's coming from.

A more interesting way would be to use a micro-controller, (eg. PIC, Atmel), to monitor the incoming PC USB data lines and through-switch to the devices - more interesting but maybe not more practical since, (as mwb1100 said), Windows would need time to identify all the devices before data could be sent through, so you'd need to incorporate some sort of RAM buffer I'd think or message back to the OS to hold until device ready is signaled.

HA! once a tech, always a tech

my electronics knowledge is rudimentary at best so that's possibly beyond my current abilities (seems like it would need some sort of control circuit to make it work) - I was thinking along the lines of a simple (analog) type switch

4wd

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Re: USB hubs - does anything like this exist?
« Reply #7 on: December 29, 2010, 06:49:53 PM »
A simple toggle switch to the control lines of a Quad Bilateral Switch, (4066 CMOS or 74HC(T)4066 TTL), is a relatively simple way to do it and it would be self-powered.  However, I'd look at making all the ports powered via external means.  You're talking about 12 ports, if they are all occupied at a relatively modest power consumption of 100mA, even with 1 powered that's still 1.1A, over twice the specified current sourcing for 1 USB port - which will be where it's coming from.

HA! once a tech, always a tech

Thanks!  ;D

Quote
my electronics knowledge is rudimentary at best so that's possibly beyond my current abilities (seems like it would need some sort of control circuit to make it work) - I was thinking along the lines of a simple (analog) type switch

Yes, you can try a 2-pole, 2 position switch and just switch the data lines.  Power the hub from an external source so you're not switching the power lines as well.  Leave the ground connected back to the computers but not the +5V.
You might need some kind of buffering, (not the data type - more to debounce the change-over), but you can certainly try it without first.

DSE - $0.99
Jaycar - $3.95

EDIT: If you want to wait a few hours, (housework - BLAH!), then I can sketch up a simple circuit using the 4066, (or TTL version), and post it up.  If you can solder two wires together it shouldn't prove daunting and the components are minimal, say ~$10.
Otherwise I do have another idea that may be mutually beneficial  >:D
« Last Edit: December 29, 2010, 07:10:00 PM by 4wd »

Target

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Re: USB hubs - does anything like this exist?
« Reply #8 on: December 29, 2010, 07:07:20 PM »
Yes, you can try a 2-pole, 2 position switch and just switch the data lines.  Power the hub from an external source so you're not switching the power lines as well.  Leave the ground connected back to the computers but not the +5V.
You might need some kind of buffering, (not the data type - more to debounce the change-over), but you can certainly try it without first.

that's more like it :Thmbsup:

so is it acceptable to leave both power lines connected concurrently?  I haven't looked at the pinouts yet, but I assume this from your comments

and how would you 'buffer' the change over?  I don't anticipate that I would be switching while anything critical was running so I do expect it would be an issue, but now I'm curious

4wd

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Re: USB hubs - does anything like this exist?
« Reply #9 on: December 29, 2010, 07:24:59 PM »
Yes, you can try a 2-pole, 2 position switch and just switch the data lines.  Power the hub from an external source so you're not switching the power lines as well.  Leave the ground connected back to the computers but not the +5V.
You might need some kind of buffering, (not the data type - more to debounce the change-over), but you can certainly try it without first.

that's more like it :Thmbsup:

so is it acceptable to leave both power lines connected concurrently?  I haven't looked at the pinouts yet, but I assume this from your comments

I wouldn't call it acceptable, there's a risk of destroying the USB device or you may have the two computers fighting each other if the voltage supply isn't exactly the same.
Since you'd be having one powered port anyway, (for external 2.5"), you might as well power them all externally - plus it's so easy :)

EDIT: Just to expand on the underlined bit.  If you switch the +5V then you're effectively disconnecting the power and reconnecting within a very short space of time.  This could induce a voltage spike into the device but I look at it this way: I wouldn't do it to my whole system, a television, or any electronic device since it has been proven in the past to kill devices.

If you leave both connected  then a fault in one computer could possibly feedback into the other - why take the chance?

I prefer to leave the USB devices powered and just switch the data lines, there's less chance of a voltage spike being induced into the data lines that way also.

Quote
and how would you 'buffer' the change over?  I don't anticipate that I would be switching while anything critical was running so I do expect it would be an issue, but now I'm curious

Did you mean don't ?

Possibly just a couple of CMOS/TTL chips wired to input/output lines, the problem being looking through specs to find what's capable of >480MHz switching.  I'd need to look through my circuit library and check the web to get a better idea and see how critical it'd be.

See my edit to my previous post also.
« Last Edit: December 29, 2010, 07:33:25 PM by 4wd »

Target

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Re: USB hubs - does anything like this exist?
« Reply #10 on: December 29, 2010, 07:34:28 PM »
I wouldn't call it acceptable, there's a risk of destroying the USB device or you may have the two computers fighting each other if the voltage supply isn't exactly the same.
Since you'd be having one powered port anyway, (for external 2.5"), you might as well power them all externally - plus it's so easy :)

I prefer to leave the USB devices powered and just switch the data lines, there's less chance of a voltage spike being induced into the data lines that way.

<light goes on> :-[

Quote
Did you mean don't ?

I do :huh:

Quote
Possibly just a couple of CMOS/TTL chips wired to input/output lines, the problem being looking through specs to find what's capable of >480MHz switching.  I'd need to look through my circuit library and check the web to get a better idea and see how critical it'd be.

See my edit to above post also.

now I'm curious about you're beneficial solution (are we going into manufacturing?)

4wd

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Re: USB hubs - does anything like this exist?
« Reply #11 on: December 29, 2010, 07:40:28 PM »
now I'm curious about you're beneficial solution (are we going into manufacturing?)

Nah, nothing so productive - just a little testing with a bit of equipment no longer in use around here - who knows maybe you'll get a simple solution and I'll get some pocket money for more Steam sales  ;D
« Last Edit: December 29, 2010, 07:43:05 PM by 4wd »

4wd

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Re: USB hubs - does anything like this exist?
« Reply #12 on: December 30, 2010, 04:06:22 AM »
Here's a circuit using a Quad Bilateral Switch, CMOS or TTL they are pin compatible - although the TTL would need to be 74HC or 74HCT series.

Parts:
4066 CMOS or 74HC4066 or 74HCT4066 (use a IC socket)
DPDT toggle switch
100nF MKT capacitor

You could wire up the whole thing on the back of the IC socket.
circuit.jpg

Here's the functional sketch bit:
scan 2.jpg

The only thing I'm not sure about is whether the internal parameters of the IC will allow full 480Mb/s without degradation but it's a simple circuit so if it doesn't perform satisfactorily then there's always the rotary switch method ;)

The other thing I have is a Belkin Flip, haven't tested it yet but I don't see why you could just not use the monitor port, connect the keyboard to one of the USB ports and a self-powered hub to the other.
If you're interested I'll give it test - I don't use it anymore since I use DVI connectors now.

Target

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Re: USB hubs - does anything like this exist?
« Reply #13 on: December 30, 2010, 05:11:49 PM »
cool, thanks!!