I figure with length the signal degrades but with short distances like 30cm is there any other negative effect?I have a pcb with an awkwardly placed usb port.. Unsoldering and connecting a panel mounted port is beyond my capabilities but i may employ some help that could execute the task if the simple cable extension affects the performance somehow.
>>101573728>30cm is there any other negative effect?Should be fine. Use a decent cable, rated beyond the target bandwidth.
>>101573857What does should be fine mean? Im obsessive about these things so i want to know exactly what and how much im loosing
>>101574092Nobody can really tell, but I'd estimate, at worst and on average, your maximum thoroughput may be limited to 95% of a direct connection.What do you want to do with this USB?I don't need more than ca. 150MB/s, because the maximum here on my system are SATA HDDs on external USB controllers.That's already too much to be used with USB2, but at the low-end of what USB3 can do, so it really depends on what you want to do with that extension wiring.
What's the use case of not just buying a longer usb cable
it's not an analog signal. the data makes it or it doesn't.
>>101574668It's transmitted via an analog medium, and has a non-zero chance of packet loss.With a million packets, this loss can become significant.With signal carrier medium degradation comes an increase in packet loss ratio, meaning less total bandwidth.
>>101574753you just send the data again. if you're rolling your own thing, just implement error checking.a cable can lose packets 99% of the time, but if you just send the lost ones again, you'll eventually transfer it all.
>>101574779usb isn't stateless like rs232 or something, the host has to communicate with a device when its plugged in and pull its ids, give it an address etc. it only tries like 3 times before it gives up.
>>101574617Midi will be transmitted over usb.. The device boasts a high hz rate of operating and i dont want to lose any of its performance power..
>>101573728if the cable is too long it takes longer for the electrons carrying your bits of data to travel over the wire.
>>101575556>MIDIAre you fucking joking? That tech is like 40 years old, its bandwidth is less than a USB2 microphone.
>>101573728From the resistive part of things:Internet says USB wires is 28 AWG (0.32 mm diameter), and the spec says +-5% voltage dropSo if we are transmitting 5V, the max voltage drop can be 0.25VImpedance between 28 and 44 so let's use worst case 28Now let's image a voltage divider, R1 is the cable and R2 is the 28 ohm impedanceVin is 5 and Vout is 4.75V, doing the calculation we get R1 must be 1.474ohmsDoing the second ohm law on a copper wire of 0.32mm and 1.474ohms, the length would be 6.933mSo in the worst case you have voltage issues above 6.9 meters, doing the same calculations with best case would be 21.785mThere's also inductive and capacitive reactances, but I'm lazy so I guess the maximum would be 6 metersBUTWhen someone makes a 25 meter USB cable, they probably use thicker wire, and this problem can be easily fixed with USB hubs or extendersUnless you are making your own cables with thinner wires or wiring usb around your house, I don't think you will have any issue
>>101573728You can use this adapter and a 200ft / 60meter ethernet cable and it'll probably be fine..https://www.amazon.com/AV-Access-Extender-Operating-Synchronously/dp/B01EV33R8SYou worry too much, you're talking about a small and cheap cable that'll probably use little bandwidth, just buy the thing and try it out.
>>101573728Depends on the speed. USB 2.0 can span quite a large distance, whereas USB 3 20Gb/s and Thunderbolt can span maybe a foot before things start getting dicey.
>>101574617>>101575698>>101575746>>101575746>>101575765Thanks to all for taking the time to advise me... Btw i only need to move the usb a couple of inches.. I was worried the extra port and the cable could introduce some kind of fuckery so wanted to make sure i dont need to desolder the port from the pcb and connect the panel mounted port directly with wires
So i was not that worried about cable length and more about the extra port and extra switch frow wire to port.. So the extra port doesn't introduce any fuckery?
