USB extension cable question

peter_4059 (Peter) · #1 28-08-2009, 08:19 PM

Is there anyone out there with experience using active USB extension cables. I am currently using two x 3 m long usb cables coupled with a powered hub but would like to increase one of the cables to 5m to get the laptop a bit further away from the scope. I'm aware of DSI cameras spitting the dummy if the usb cable is too long but was wondering if an active USB extension cable would do the trick.

Where do you get these from and are the good/bad brands out there?

Thanks,

Peter

Tandum (Robin) · #2 28-08-2009, 08:38 PM

Where did you hear about these peter? I'm not aware of them at all.

As far as I know the usb problem is, more than 5 meters without a powered hub and you suffer signal loss. More than 3 hubs (or is it 5?) and you suffer time outs from signal delays due to hub buffering. Active cable?

peter_4059 (Peter) · #3 28-08-2009, 08:45 PM

I've heard people refer to them and if you google active USB extension you get plenty of hits. They claim to be able to extend a long way past 5 metres. I'm interested to know how successful this is. They appear to be powered from the usb port so not sure if they are any different to a normal extension cable?

http://www.mittoni.com.au/usb-20-5m-...le-p-1321.html

Tandum (Robin) · #4 28-08-2009, 08:54 PM

Looks like a single port unpowered hub on the end of a cable. I doubt there'd be enough juice left at the end of a 25 meter run to power up anything

I guess you could always put a powered hub on the end of the run

PeterM · #5 28-08-2009, 08:57 PM

I use a quality powered USB hub for the 10 metre cable that runs my Starlight Xpress Camera. Without it and over 5 metres the camera just drops out regularly. Same thing happened when I had a DSI camera - it was then that I read somewhere that there are powered USB ports in laptops and non powered ports and that the DSI needed a powered USB port, again limited to about 5 metres. As far as active USB cables go I believe that Pat Pearl has recently bought some (and may have a good supplier) and is able to extend a considerable distance (10 meters plus I think). Might be worth giving him a call Peter.
PeterM.

MrB (Simon) · #6 28-08-2009, 09:01 PM

I think you need a remote power supply if there needs to be a decent current draw.
An alternative to long USB cables is a USB--->CAT5--->USB converter.
Have these at work but I've never tried them, sold a few though and never had a return yet, so I guess they do work.

Tandum (Robin) · #7 28-08-2009, 09:06 PM

How much are they Simon? Can they handle a hub at the other end?

Never mind, I looked em up. $50 and usb1.1

peter_4059 (Peter) · #8 28-08-2009, 09:18 PM

Thanks Peter - I'm catching up with Pat on Monday night for the Astrofest washup meeting so will check out what he has then.

Peter

g__day (Matthew) · #9 28-08-2009, 09:23 PM

You can daisy chain a maximum of 5 lots of 5m provided every cable is an active extender (the ones with the small matchbox sized female heads where they connect - they retail for between $30 - $50 each).

I have done in reliably with 3 * 5m - 5 * 5m can be a bit dicey - should work with a bit of luck! Try it a step at a time.

PS

If you're going to add a hub - make sure its a powered one - else you're in for disappointment!

peter_4059 (Peter) · #10 28-08-2009, 09:26 PM

Matt,

Do you know what's inside the matchbox end? It looks like all the power is still supplied from the laptop USB port?

mithrandir (Andrew) · #11 28-08-2009, 11:28 PM

Quote:

Originally Posted by Tandum

How much are they Simon? Can they handle a hub at the other end?

Never mind, I looked em up. $50 and usb1.1

If you don't mind throwing $$$$$$$$ you can get toys like this, http://www.smartvm.com/Icron-USB-2.0...iber-P9663.htm

"... extend USB 2.0 peripheral devices up to 10km over fibre optics at up to 480 Mb/s."

~$US1K

troypiggo (Troy) · #12 28-08-2009, 11:51 PM

Oooh, you need one of those....

TheDecepticon · #13 29-08-2009, 12:33 AM

I use one all the time. No dramas, and I run a DSI Guider, DSI Pro II, used to run a 40d, game controller, GPUSB and USB to serial adapter all off one 7 Port High Speed USB2 powered hub, going through the one 5 metre Active USB cable. Try Bintel or a computer store.
Also, there are different grades of USB2 cables. Make sure you get genuine "High Speed USB2" cables, which are marked with a symbol on the cable ends, stating that they are "High Speed USB".

Tandum (Robin) · #14 29-08-2009, 01:02 AM

Do you know the difference between a "High Speed USB" cable and a normal USB cable?

Tandum (Robin) · #15 29-08-2009, 01:03 AM

Marketing ....

Exfso (Peter) · #16 29-08-2009, 01:30 AM

I got 2 of the Active USB cables and they work a treat, got mine from Dick Smith, from memory about $30.00, prior to these, I tried piggy backing ordinary USB cables, this cause the laptop to have a real hissy fit all the time. No sign of this behaviour since the aquisition of the active cables.

MrB (Simon) · #17 29-08-2009, 03:04 AM

Quote:

Originally Posted by Tandum

How much are they Simon? Can they handle a hub at the other end?

Never mind, I looked em up. $50 and usb1.1

DOH!
Didn't know that.

dugnsuz (Doug) · #18 29-08-2009, 07:44 AM

I use 2 linked USB extender cables with no problems - Laptop to 3 port hub on telescope (DSLR/Webcam/GPUSB)

Approx $25 each at Jaycar.
http://www.jaycar.com.au/productView...e&form=KEYWORD

Doug

AlexN · #19 29-08-2009, 10:27 AM

I run 5m cables to everything on my setup.. despite the fact that a 3m cable would suffice most of the time, I like the extra flexibility should I want to move my laptop further from the mount etc..

I've never had an issue.. I've done 1x5m usb cable to powered 4 port hub split to QHY8, GPUSB, FCUSB and DBK31.
I've done 1x5m to Orion SS Pro, 1x5m to QHY5, that worked well too..

I have never seen the need to be further than say, 3m from the mount... Seems silly to me.. just make sure you have a light shroud around the laptop screen and have it pointing in a direction you do not plan to image...

g__day (Matthew) · #20 29-08-2009, 02:40 PM

Short answer - no idea of the circuitry inside the end of an USB 2 extender - but I presume it filters and purfies signal, not just boots power.

Secondly I have tried the USB <-> cat 5 <-> USB devices - never with any success because it appears Windows can't work out what is on the other end of the cable and never loads the CCD driver. There may be a way of getting this to work - but I never discovered one.