USB extension leads - Page 1
Forum section: electronics / general

author: Flump
author_rank: Frequent Contributor
timestamp: August 13, 2014, 10:06:00 am
content: How do you guys decide what USB extension to buydo you just buy one that looks good and take a chanceor do you stick to a specific brand or something else ?I just got one from ebay which looked great and he soldover 12000 of them but testing it for charge currentI got about 60mA out the other end of it when I pluggedmy torch in to it which should have drawn about 370mAhttp://www.ebay.co.uk/itm/370782294942?_trksid=p2059210.m2749.l2649&ssPageName=STRK%3AMEBIDX%3AITresistence from one end of each wire to the other is around 1.6Rand thats a 1mm drill bit in the picture

author: jakeypoo
author_rank: Regular Contributor
timestamp: August 13, 2014, 12:16:37 pm
content: Technically, USB extensions are not USB compliant. If you insist on using them, get the thickest gauge power conductors you can find. As for data, if you are transmitting anything at hi-speed you might have problems. If you need to extend USB for some reason, use a powered hub.If you want to stay within spec for cables (which I have found is necessary if you want to charge modern mobile devices with a dedicated charger) stick to the USB 2.0 cable guidelines for power conductors:28AWG for <= 0.81m26AWG for <= 1.31m24AWG for <= 2.08m22AWG for <= 3.33m20AWG for <= 5.0m

author: SL4P
author_rank: Super Contributor
timestamp: August 13, 2014, 12:25:59 pm
content: There are *good* usb extensions out there - but none I've seen will really suit charging applications.The best cables (I have 2 x 10m in my goodie box) use a couple mA of power from the source - to reshape/reclock the data pins.

author: VK3DRB
author_rank: Super Contributor
timestamp: August 13, 2014, 12:28:15 pm
content: Very good question. There is a lot of junk USB cables around. Not only from eBay but also from your local computer store. I have seen similar things with normal USB cables, not extension cables. Some I/O devices such as cameras won't work with crap cables. The only ones I trust is those supplied with brand name equipment, and also my never failing Microchip PICkit/3 red mini USB cable. Looking at the price on eBay, you got what you paid for.Maybe something like this is better...3M USB 3.0 SuperSpeed Extension Cable Insulation Protected Male to Female MFor this...http://www.ebay.com.au/itm/High-USB-3-0-Type-A-Male-to-Female-Connector-Extension-Cable-Adapter-Blue-/161377525870?pt=AU_Laptop_Accessories&hash=item2592d9a06e&_uhb=1USB 3 by definition can provide higher currents, so one would hope the cables have a decent wiring gauge.Why are most USB cables one confusing and boring colour? It is better if they are different colours. Same with power cords, so you pull out the right one. Same with cars, but there are many fools around who prefer dangerous camouflaged coloured cars.

author: Flump
author_rank: Frequent Contributor
timestamp: August 13, 2014, 08:43:46 pm
content: Jakeypoo -thanks for the info it's useful but when buying USB leads online they don't listthe conductor wire gauge.vk3drb-very good idea about USB 3 leads, unfortunately your links didnt work for me.I am going to buy one of these 3M long-http://www.ebay.co.uk/itm/400725406451?_trksid=p2055119.m1438.l2649&var=670269920472&ssPageName=STRK%3AMEBIDX%3AITUSB 3.0 EXTENSION CABLE Mainly Used In External Hard Drives,High-Resolution Webcam,Video Monitor,VideoDisplay,Usb Interface Digital Camera,Digital Camera,Ray Drive,etc100% Brand NewSupports data transfer speeds of up to 5Gbps—10 times faster than USB 2.0This cable supports higher electrical currents to meet the greater electricaldemands of bus-powered USB 3.0 devicesBackwards compatible with USB 2.0 devicesConnector: USB3.0 Male to USB3.0 FemaleAvailable Cable Lengths: 1, 1.5, 2, 2.5 & 3 MeterColor: Bluewhen it comes I will do a charge current test on it.

author: Precipice
author_rank: Frequent Contributor
timestamp: August 13, 2014, 09:04:22 pm
content: A slightly different question - does anyone know where to get raw USB cable (on a reel) from?It's tricky to find a search that works.

author: Flump
author_rank: Frequent Contributor
timestamp: August 13, 2014, 09:19:52 pm
content: for USB cable you need 4 conductors and an overall screensearch ebay for 4 core screened cable reeland buy the best cable you can afford if you are going to make long runshttp://www.ebay.co.uk/sch/i.html?_odkw=4+core+screened+cable&_osacat=0&_from=R40&_trksid=p2045573.m570.l1313&_nkw=4+core+screened+cable+reel&_sacat=0

author: Precipice
author_rank: Frequent Contributor
timestamp: August 13, 2014, 09:26:20 pm
content: It needs to be the right impedance (90 Ohm, iirc somewhat unusual), and the data pair should be screened, and the power pair should be thicker gauge... By the time yo meet that lot, you're looking at something specifically USB, I think.For that project, I ended up butchering good USB cables, but that's a pain - not least because the annoying plated shield strands are very hard to solder.

author: Flump
author_rank: Frequent Contributor
timestamp: August 13, 2014, 09:57:03 pm
content: I have never seen USB cables like thatnormally they are 4 of the same conductorswith an overall foil screen.your's sound the proper way to do it though

author: Flump
author_rank: Frequent Contributor
timestamp: August 13, 2014, 09:59:24 pm
content: this is quite interestinghttp://voyager8.blogspot.co.uk/2013/04/how-to-choose-good-usb-data-and.html

author: jakeypoo
author_rank: Regular Contributor
timestamp: August 14, 2014, 01:34:35 pm
content: Quote from: Precipice on August 13, 2014, 09:04:22 pmLCOMM Has bulk usb cableOr use search term "bulk USB cable"

author: Precipice
author_rank: Frequent Contributor
timestamp: August 14, 2014, 02:14:10 pm
content: Aha, thanks! Bulk was the word I couldn't guess.