Know of a USB switch that actually works?

[mubs]

Howdy Doody! I need advice from the wise folks here.

I have to share a bunch of USB peripherals between a PC and a notebook that will come and go.

The peripherals were all directly on the PC originally. These include USB DSL modem, an Epson inkjet with a factory USB interface, an HPLJ 4ML with a parallel to USB converter that I installed, etc.

First step, bought a Belkin 7-port powered hub (F5U027), and hooked up all of the peripherals to the hub. Everything works fine with the PC.

Next I called Belkin Tech Support, and they told me to buy the 4-PC USB switch (F1U200). Their site and the product literature say the switch allows 4 PCs to be connected to one USB peripheral or hub (with upto 127 devices on the chain), and to switch between the PCs at the push of a button, round robin style. The Tech support bloke assured me it would work. It's a passive device and is not powered; I guess it draws power from the hub.

Well, it doesn't work :x . All of the testing I did was with the PC only, the notebook was not even ready to test at this point. As long as the hub is directly connected to the PC, everything works fine. With the switch between the PC and the hub, only the DSL modem works. Even the Epson inkjet with the factory USB interface will not print; Windows says there was an error, etc. I called Belkin Tech support, and the guy blamed me for it; he said many peripherals need to be directly connected to the PC and won't work with the hub. I had to repeatedly point out that everything worked fine with the hub, it was the switch that was causing the problem. He went on and on about how it was my "responsibility" to ensure everything would work, and they were not responsible, etc. etc. He went on giving me BS and each time I corrected him on a fact, he'd cook up another piece of BS. I'll spare you all the details; needless to say at one point I just hung up on him :evil:.

The package says it is compatible with USB 1.0 devices. None of my devices are 2.0. But is there a significant enough difference difference between 1.0 and 1.1? I brought this issue up during the tech support call, but the guy dismissed it as being of no consequence. I bought the switch on the internet from OfficeMax; they probably gladly dumped obsolete stock on me? Few B&M stores seem to carry this; apparently not a hot selling item. SO I’m unable to verify the version before I buy it.

I'm going to return this POS to OfficeMax. Now what do I do next? Worst case option is to plug/unplug the cable that comes from the hub into and out the PC and notebook as necessary. Apart from the wear and tear on the contacts, it's a clumsy option (it'll be happening every night when the notebook comes home from work). I don't think it's the cable length; 6ft from PC to switch, 6ft from switch to hub makes a total of 12ft. No cable from the hub to a peripheral is longer than 6ft, and since the hub is powered, I'm well under the "16ft maximum" limit.

Anybody know of a switch that actually works, or another way to solve this problem? Thanks a bunch.

 

[blakerwry]

Have you considered a USB based KVM switch from IOgear? I believe they take stuff manufactured by other companies and slap their case and name on the outside... but I have read good reviews of their 2 and 4 port KVM switches.

As with anything, do some research before buying... I especially look for reviews and comparisons when shopping for such items.


http://direct.mwave.com/mwave/doSearch.hmx?bop=and&scriteria=iogear+USB+kvm&UID=&CID=&Back=&n=1

 

[Fushigi]

If both PCs are networkable, leave the USB devices in the hub attached to the main machine. On that PC, share everything you want the laptop to be able to use. On the laptop, access the devices over the network. You don't even need an Ethernet hub if you get a crossover cable; just plug the laptop into the desktop.

I used to do something like this before I got my 802.11b WAP, which includes a printer port for sharing.

- Fushigi

 

[mubs]

Blake, I'm a little confused about the USB KVM suggestion. I'm not sharing keyboards or mice; not sure how a KVM would fit in my scenario.

John, if I had only printers, that's the route I would have taken--far cheaper and easier. The difficulty is in sharing the USB DSL modem (AOL!!!) and the Visor Prism USB sync cradle. I'm not sure how well you can share scanners either.

This setup is not for me but for a non-geek who's always paralyzed with fear when confronted with anything out of the usual routine when it comes to computing.

Blake and John, thanks for the suggestions, though.

 

[Cliptin]

Did you try to set the switch to the correct channel and then plug in the usb cable to the computer?

 

[blakerwry]

the USB KVM switch can handle more than just keyboards and mice... it is supposed to b able to be hooked to a hub and you can share *ANY* USB device... I believe the documentation specifically mentions printers and/or scanners.. but it might of just been the site I was looking at.


I don't know if it is the best solution though since it offers more than you really need and costs consoderably more than a simple USB switch.

 

[Fushigi]

John, if I had only printers, that's the route I would have taken--far cheaper and easier. The difficulty is in sharing the USB DSL modem (AOL!!!) and the Visor Prism USB sync cradle. I'm not sure how well you can share scanners either.

Internet Connection Sharing will let the DSL be shared over the mini-network. My W2K PC dials in and the other PC & laptop share the connection; there's no good reason why this wouldn't work for any connection. It's basically using the PC with the connection as a router.

As to scanning .. scan on the desktop & just transfer the files to the laptop as needed. Consider it a way to backup the scans. We download images from our digicam to my wife's PC. Periodically I back up the folder with the images to my machine.

The cradle, I can't help with. I suppose that one device could be switched over as necessary.

- Fushigi

 

[mubs]

Did you try to set the switch to the correct channel and then plug in the usb cable to the computer?

Yes Cliptin, I tried that, didn't help. Besides, wouldn't that defeat the purpose of having a switch?

Blake, I paid $30 for the switch that didn't work (no grins, please, that was a Belkin); KVM's that support USB seem to be at least a couple of hundred!

John, ICS is fine, but the ISP here is AOL. To get mail, one has to be signed on with one's screen name AT the computer that has the Internet connection. It is possible to check your AOL mail through the Internet, but there are limitations that are not acceptable on an ongoing basis. The user does indeed check his AOL mail throught the Internet, but needs to be able to download attachments and do a lot of other things (like AOL content) that are possible only with the "direct" conenction. I'm not an AOL user (can you picture me with a finger in my throat?), so I have to rely on the user who's been with AOL for ~10 years. AOL is also very restrictive with ICS; 3 months ago I tried to make a W98SE system that was running AOL share its connection, and after spending hours being unsuccesful, found something on MS's website that W98 + AOL != ICS.

I'm not being critical of all of your suggestions; I appreciate the time and effort you all have taken to help. It's kind of a weird situation, though.

 

[blakerwry]

the IOgear KVM's I linked to started at ~$100 I thought....

I have seen USB KVM's locally for under $100... but yes, USB switches start at $30 and goto about $60 before you start to say "hmmm"....

Supporting Fushigi, as far as I know you can install AOL and tell it to use a LAN(or TCP/IP) connection... I have done this at my house so a friend could use AOL from my cable modem service (road runner). My computers go through a NAT router... so I would suspect it's possible to use AOL through ICS.

 

[Tea]

Mubs, I suspect that, despite your careful measuring, you are running into cable length problems (effectively, if not in strict point of fact). As a general rule, every time you add a mechanical connection, or more particularly a swoitch, you add noise to the system, and possibly add delay as well. If the USB switch is mechanical, it will have inductance. If it is solid-state, it probably adds some delay. (Ask JTR this stuff - that's right down his alley.) Either way, the extra plugs will have add a little signal degradation too.

Take two 2m cables and the switch. Let's say that the cables and their associated mechanical connections degrade the signal by 5%. (Just a number I made up for the sake of example.) The switch degrades the signal by 20%. Total signal loss is 30%, and your typical USB device can tolerate anything up to 50%, so the system works. (Again, just made-up numbers.)

Now take two 6m cables (they are longer, so 10% each) and the hub (20%). (Forget the switch for now.) Another 40% total signal loss, so the system still works.

Slip the switch back in and we have 60% loss. Most of your devices give up the battle. Only the especially tolerant ones still work. You might just get away with it by using shorter cables, or you might not. Test the theory out - it is just a theory - by taking two short USB cables and the switch, and trying each device in turn. If that works, go through the possibilities. After a while you will be able to draw yourself a mental map of the things that work and the things that don't work. Armed with that, you can start to make decisions.

PS: Anyone know what the USB cable length restriction has to do with? Is it noise? Signal attenuation? Or timing considerations?

 

[blakerwry]

just a side note.. at microcenter I saw a mechanical USB KVM siwtch for $30-$40...


Tea's hypothesis might be correct... but it dumbfounds me how just a few yards of USB cable could be too much (even when hubbed/switched). You would think that the hardware/tehnology would be more robust.

 

[Fushigi]

You would think that the hardware/tehnology would be more robust.

But you would be wrong. :lol: I thought so as well, until I tried to download a few hundred photos from my digicam in a single pass. After the first 120 or so, about every other image had errors. Either in color rendering or parts of the image from a certain point down would be shifted to the right or left a little bit. The images on the microdrive in the camera were fine and when I re-downloaded them individually or in smaller groups I have no problems at all.

Apparently, there's little-to-no error correction capabilities in the USB protocol. Or, the capabilities exist but are optional. The environment was digicam to the Canon-supplied USB interface cable (about 4 or 5 feet long; maybe 6 ft) to the motherboard USB port. No switches or hubs.

So, if USB apparently has no (or optional) error correction capability, should it really be trusted for storage? What about 1394/firewire?

- Fushigi

 

[Tea]

Good point, Fushigi. Anyone know enough to expand on this with a wrap-up of error correction and external connection methods? We should know thiz ztuff.

 

[mubs]

AAAAAAAAAAAAAAAAaaaarrgh!!!! I logged in and typed a 1000000 word reply and hit preview and it cleared the screen and asked me to login again!!! I have to run now; will come back later. Sorry.

 

[blakerwry]

one million words, eh?

were you counting only unique words? or the total number of words used in the reply? does that include a quotation from another source?

 

[Tea]

You are a cruel, cruel man, Blakewry.

Have a banana, Mubs.

 

[blakerwry]

The same could be said about a certain banana eating primate we both know.

http://storageforum.net/forum/viewtopic.php?t=1574#23959

 

[mubs]

All right, folks! I'll cut to the chase: everything woiks like I had wanted it to!

And John/Blake: Have you ever used ICS with AOL?? Not a trivial task, if you can get it to work at all. We can go into gory details if you wish, but I'll spare everybody else the pain.

After much reflection (thanks to Tea {Tea, do remind me to ship you a create of bananas}), I visited http://www.usb.org/home. I had been under the impression that 5 metres (16' 5") was the maximum length of a USB cable. But this is true only for full speed devices. For low speed devices, the limit is 3 meters (9 feet 10 inches).

Aha! I'll betcha printers with USB interfaces (the cheaper ones anyway) are low speed devices. Even the ones with the factory USB interface, like the Epson Stylus Color 980 used in this case. And of course, the $2 (closeout price, still available) Xircom/Entegra parallel to USB converter I stuck on the HP LaserJet 4ML HAD to be a low speed device.

I went to the local Fry's Electronics spent a good couple of hours poring over every USB thingy they had. I bought a 4-PC to 1-device electronic USB switch made by Aten (they're better known for their KVM switches), model US401. And two 3-foot USB device cables made by APC (yes, the power people, and very well made they are too).

Also bought a 15-foot "active" USB extension cable; the notebook is some 6 feet away from the rest of the stuff, and by the time the cable is routed properly so it doesn't get in the way, it needs to be 14+ feet. Strangely enough, many manufacturers make 15 foot extension cables without a repeater built in. That means 15 ft + the length of the device cable, and you're out of spec already. The repeater acts like a one port built-in hub.

Anyway, I hooked up the repeater cable to the notebook and to the cable from the hub (15+6 ft) and everything worked fine. Hooked up the desktop to the switch using the 3 ft device cable, and the hub to the switch (6 ft device cable), and everything worked fine. Finally hooked up the repeater cable from the notebook to another 3 ft device cable which went into the switch (and on the the hub) and that woked too! So I'm all set now.

I didn't (and don't plan to) try the Aten switch with the 6 ft cable connecting it to the desktop, like I had with the Belkin switch. I don't know if it would have made a difference. Belkin claims (extracted from product page of their web site):

* Share one or up to 127 USB devices with up to four USB computers
* Works with virtually all USB 1.1 compatible computers and devices
* Compatible with virtually any USB computer or USB device
* Support for virtually all high- and low-speed USB devices
* USB 1.1 compatible

Lessons I learned: As Tea said, use the shortes cable you can. Large, well-known mfrs. make lemons too.

If anybody is looking for the shortest USB cables around, http://www.pccables.com/ in Florida has USB 2.0 device cables 18" long. I almost placed an order for them, but decided to try local stores to save time.

Thanks everybody!

 

[mubs]

Yikes, I forgot price info.

Aten switch model US401: $30
IOGear Active Extension cable 15': $30
APC USB 2.0 3 ft Device cable: $5.49

PCCables sells a 15' active extension cable for $15; USB 2.0 device cables are $2.29 for 3 ft and $1.99 for 18".

 

[blakerwry]

man.. USB sucks...


Im going to look up firewire specs

 

[blakerwry]

hmm seems like 15 feet is what the official firewire 1 specs claim. Although it says you can daisy chain devices to get longer distances(possibly upto 72 meters).

Firewire is also a p2p based bus (evey device on the chain can talk to every other device on the cahin without the need for a host controller... cool!

A new version, IEEE 1394.B, is in the works and will support speeds of up to 1.6 gigabits per second and extends the maximum cable length to 100 meters

The goal of the 1394b spec is also to increase the maximum length of eachhop from 4.5 m to 100m. To do so, new media needed to replace the existingcopper cables. 1394b supports long distance transfers up to 100m over a varietyof media: CAT-5 unshielded Ethernet and UTP-5 patch cable at 100 Mbps,existing plastic optical fibre (POF) at up to 200 Mbps and next generationPOF at up to 1600 Mbps, and 50-micron multimode glass optical fibre (GOF)at up to 3.2 Gbps. The table below (figure 4.4) summarises the forms of mediasupported and their respective speeds and range capabilities

More at: http://212.201.48.1/birk/lectures/comparch/reports/ieee1394paper.pdf

 

[mubs]

Yup, Blake, USB sucks. USB's coming up with the "P2P without the need for a host" concept; it's called "USB To Go" or something like that.

If only Apple hadn't tried to charge the royalty they did, USB wouldn't have had a chance. Unfortunately many mfrs. still don't put FW in their machines; many Dell notebooks, for instance.

Is there a device (hub?) that will support both USB and FW AND translate protocols automatically between the two? If not methinks there's a good market for such a device.

 

[time]

Aha! I'll betcha printers with USB interfaces (the cheaper ones anyway) are low speed devices. Even the ones with the factory USB interface, like the Epson Stylus Color 980 used in this case.

I just reread this thread, and I'd like to add that I've successfully tested low-end Epson printers on USB cables up to 6m (5m + 1m extension). I suspect they're pretty good cables though (not Belkin )

I'd also conclude from Mubs' experience that ATEN products are excellent value (about to pick up a couple of their KVMs) - unlike Belkin.