13-11-2024, 04:29 PM
With USB C (the connector) & 3.2 (the protocol), you can get severe signal degradation over more than a couple of metres, even with decent cables. Many cables only have a selected number of the full range of connections available - They may not support all the Power Delivery (PD) options that the devices you plug into use - there are at least 3 different "standard" PD specs, (1.x, 2.x & 3.x) but the standards also allow some manufacturers to have custom PD signalling - e.g. the Raspberry Pi 5 is non-standard, using 5V at 5A, where the normal standard only allows 5A once you're above 20V and 3A below that, but the RPi lot don't want a high current DC-DC buck converter on the board, so needed 5V @ 5A to drive the board and to supply power to all its own USB A ports... However, the USB PD specification R3.1 v1.8, Table 10-2 footnote 2 says "The Fixed PDOs Maximum Current field Shall advertise at least 3A, but May advertise up to RoundUp (PDP/Voltage) to the nearest 10mA. Requires a 5A cable if over 3A is advertised." R3.2 V1.0 came out in April this year but I don't have a copy to hand.
Also, USB high power charging cables generally need to be pretty short to prevent significant power loss. There are many many cables in the market with bonkers claimed specs just trying to outdo the next guy - the market is riddled with poor quality cables that look pretty but get nowhere near their claimed specs.
Over about two meters, for signalling cables, you need to switch from normal "passive" to "active" cables.
Proper active cables (from folk like Lindy) do signal shaping and have inbuilt differential line drivers etc. I have full speed (10Gb/s) USB 3.2 Gen 2 5mtr USB C active cables that work flawlessly into proper powered USB 3.2 Gen 2 hubs - passive cables had dropouts all the time.
You pay significantly for that privilege, but it works perfectly. The main cables I use are USB 3.2 Gen 2, C to C, https://www.lindy.co.uk/cables-adapters-...ble-p13340
Warning: there are a lot of fake or below spec USB C "active" cables. Buying from AliExpress, eBay or Amazon? Good luck with that! Real ones will be really quite expensive as there's a lot going on inside them. I chose Lindy as they are a highly reputable company plus they design & make their own active cables and test each one before delivery - I got to speak directly with the engineers in the UK & Germany.
Also, USB high power charging cables generally need to be pretty short to prevent significant power loss. There are many many cables in the market with bonkers claimed specs just trying to outdo the next guy - the market is riddled with poor quality cables that look pretty but get nowhere near their claimed specs.
Over about two meters, for signalling cables, you need to switch from normal "passive" to "active" cables.
Proper active cables (from folk like Lindy) do signal shaping and have inbuilt differential line drivers etc. I have full speed (10Gb/s) USB 3.2 Gen 2 5mtr USB C active cables that work flawlessly into proper powered USB 3.2 Gen 2 hubs - passive cables had dropouts all the time.
You pay significantly for that privilege, but it works perfectly. The main cables I use are USB 3.2 Gen 2, C to C, https://www.lindy.co.uk/cables-adapters-...ble-p13340
Warning: there are a lot of fake or below spec USB C "active" cables. Buying from AliExpress, eBay or Amazon? Good luck with that! Real ones will be really quite expensive as there's a lot going on inside them. I chose Lindy as they are a highly reputable company plus they design & make their own active cables and test each one before delivery - I got to speak directly with the engineers in the UK & Germany.
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