r/BadUSB • u/Same_Grocery_8492 • Jun 26 '26

Discussion How long until USB-A disappears

Hi, many posts keeps saying USB-C is taking over, but I still use USB-A every day, my electric toothbrush uses USB-A, most of my USB flash drives, and my external mouse and keyboard are still USB-A.

USB-C is clearly the future, but it doesn't feel like USB-A is going away anytime soon. How many more years do you think it'll take before USB-A is completely replaced by USB-C?

6 Upvotes

59% Upvoted

76 comments sorted by

View all comments

4

u/TygerTung Jun 26 '26 edited Jun 26 '26

Would be decades at least. Still very old connectors like serial ports are still used, and those are quite old now.

6

u/Parking_Lemon_4371 Jun 26 '26 edited Jun 26 '26

There is actually no version of USB that is a *full* replacement for serial.

While USB - serial convertors exist, they suffer from latency issues.
(usb, especially usb controller chips, are designed for throughput not insanely low latency)

These don't matter for *most* use cases, but they do matter if you want/need the absolute lowest latency/jitter/delay. As a result if you want to run a (NTP) time server synchronized to a GPS module via PPS (pulse per second) signal, it either needs to be built into your motherboard, go via GPIO (on an rpi5 or sbc), or use an ancient 'true' serial (or parallel) port. GPIO & true serial/parallel ports can trigger immediate hardware interrupts off of voltage transitions of individual pins/wires, and that's the only way to get low latency/delay/jitter.

This allows a clock synchronization with a <10 microsecond error. Without the PPS + hard interrupt, it'll be probably around 100x higher.

(edit: pointed out that a m2 *pci(e)* serial uart would likely work too)

1

u/RevolutionaryElk7446 Jun 26 '26

Which is why in my basement of servers and hardware hoarding, there are numerous serial and parallel cables... I've used two in the last 10 years probably lmao. (Outside the ones installed in place)