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Grierson

USB leads

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Having recently received a new ASIair I am keen to tidy up the cabling on my rig. I'm having great difficulty finding leads of specific lengths. (e-bay and Amazon) i.e. 2ft USB2 A to B with the A being a right angle plug. I wonder is anyone has a source of leads with oddball lengths. Thanks - John  

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I've sometimes resorted to buying the cable length I want and the right-angle plug separately when I wanted this sort of thing, then fixing them together with insulating tape.

James

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55 minutes ago, PeterCPC said:

You could try here

Peter

Thanks Peter but I need three and at £60+ I would have to live with the untidiness 😀

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22 minutes ago, JamesF said:

I've sometimes resorted to buying the cable length I want and the right-angle plug separately when I wanted this sort of thing, then fixing them together with insulating tape.

James

Thanks James, I’ve never tried to cut in to USB leads to fit plugs but I would guess the required precision soldering involved would now be beyond my old eyes. John

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if you can get the pre-made lead length you need then you could consider getting right-angle adaptor to suit that just plugs onto the end of the lead. Insulate from moisture ingress with dielectric grease or perhaps heatshrink or self amalgamating tape.

something like: (there's several types)

https://www.amazon.co.uk/Adapter-Degree-Female-Coupler-Connector/dp/B0734HQ178/ref=sr_1_3?keywords=right+angle+usb+adapter&qid=1579434871&sr=8-3

 

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2 hours ago, Grierson said:

Thanks James, I’ve never tried to cut in to USB leads to fit plugs but I would guess the required precision soldering involved would now be beyond my old eyes. John

Ah, that's not what I had in mind.  Clearly I didn't explain very well.  What I meant was to buy a lead of the right length with "straight" connectors, then put something like this on the end:

https://www.amazon.co.uk/Adapter-Degree-Angled-Connector-Extender/dp/B01MRRNX0R

Then wrap the join in a few loops of insulating tape so it can't come apart easily.

Sometimes it's the only way I've found to get quite the combination that I want.

James

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I would suggest getting the right cable without adding adapters. You can get pretty much any combination of length, connector and orientation from Aliexpress. Although with the Chinese new year coming in a couple of days, it's best to order soon, or wait until Feb.
If you are concerned about quality issues, I fully expect that any UK supplier gets their product from the same/similar source. Unless they fabricate each one themselves.

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Thanks Pete, I’ve had a brief look and it is not immediately obvious how specific lengths and terminations are specified/ordered but I will dig a bit deeper. - John

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I get my angled USB cables from Amazon.  They have a huge variety.

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A general word of caution  on USB cables if I may?

USB leads may appear to work OK in certain places but not in others. The seller may insist it is a good cable, though you think otherwise.

USB leads do two distinctly different jobs.

First they can provide power. Whether to charge a battery, run a camera, run a comms protocol convertor, etc.
Second they need to carry data.

In 'ordinary' USB connectors the outermost pins are for power, the inner pins for data.
I won't get into identifying chage/power types and USB-C as the post will get very long🤐

Sometimes a USB lead provided with a device that only uses power will have the data part of the cable missing.
It charges your phone but won't connect it to your computer!

Sometimes a USB lead intended for data has thin (high resistance) power leads.
Use this cable to link two devices to transfer data and all is OK.
Use this to power a (hungry) camera, or charge a battery pack in a tablet and you have problems.

Then there is the 'quality' of the data wires. They should be a twisted pair of wires for optimum high speed data transfer.
But to save a penny or two, if you don't twist them, you can transfer data slowly, or over short distances, or between certain devices.
Other devices that are less tolerant of poor signal levels or timing may not work very well.

Then there is the question of a screen over the cables.
Put an unscreened cable in the vicinity of devices generating electrical interference and you will have problems.
For example if you run a USB cable next to the mains cable for a switched mode power supply and expect problems.
A screened cable has a copper braid or foil over the data and power cables. This connects to to the plug frame.
These cables are far more likely to give good performance in a 'nasty' environment.

Then there is the question of the wire insulation. Nice and flexible in the home.
But what about at -10C on your scope?
If in doubt, leave your proposed leads in the deep freeze, then bend to see if they snap. Yes some cables do snap!

So an ideal USB cable contains a twisted pair for data. Also two really thick cores for power. Around it is good braid screen.
It has 'arctic grade' or similar insulation.
It is expensive and probably not that flexible because of the braid and thick power wires!

In any USB connection regime, try to do the long run with one cable and plug at each end.
Several short cables strung together risk losing data integrity and increased resistance (on power connections) at every joint.

Remember the recommended limit for USB is 5 metres maximum. That does not mean 5 + 5 + 5 metres by stringing leads together.
Always use some sort of buffering device for longer runs.

If you are trying to copy a few photos from your phone, or charge it and have a few issues, it is not the end of the world.

But if you are running imaging equipment with multiple USB devices, that is a very different situation.
You possibly expect all of the kit to run from USB power. You expect to set up at room temperature and everything still works at -10C.
You set up and walk away. Hopefully capturing several hours of images on your £5K scope from the one clear night in the month.
Are you going to trust all of this to a 99p from ebay or Amazon Marketplace seller?
Or are you going to buy a premium cable from a known name manufacturer?

Unfortunately outright price does not always ensure good quality. There is an element of trial and error.😕

HTH, David.

 

 

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Phew David thank you for taking the time to post comprehensive comment. The answer is NO to your penultimate paragraph question. The problem is getting bespoke lengths/terminations from recognised manufactures is clearly a very expensive option.

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