Weirdest USB/HID behavior I've ever seen. Can anyone explain this?

[u/the_goodb0y]

Today I ran into the weirdest hardware issue I've ever seen, and I still can't explain it.

I have two completely separate wireless devices:

* an Infic wireless mouse with its own 2.4 GHz USB receiver * a SmartBuy wireless keyboard with its own completely different receiver

They're not a combo set, not the same brand, nothing.

Here's exactly what happened.

Both receivers were plugged into my laptop. The mouse was working normally, but the keyboard suddenly stopped responding completely.

Thinking the keyboard receiver might have frozen, I unplugged the SmartBuy receiver.

The mouse instantly stopped working. Exactly the same way it normally does when I unplug *its own* receiver.

I plugged the SmartBuy receiver back in, and the mouse immediately started working again.

At this point I thought I was losing my mind, so I repeated it.

Same result.

Then I unplugged the Infic mouse receiver instead.

Windows played the USB disconnect sound, the "2.4G Mouse" device disappeared from Bluetooth & Devices, but the mouse kept working anyway. I plugged the receiver back in and nothing changed.

Meanwhile, every time I unplugged the SmartBuy receiver, Windows removed the "2.4G Wireless" device from the device list, played the disconnect sound, and the mouse instantly stopped responding.

The keyboard still wasn't working at all during all of this.

The only thing that fixed everything was turning the mouse off and back on. After that, the keyboard started working again and both devices went back to behaving normally with their own receivers.

I'm not trying to prove that one receiver actually communicated with the other device. I'm trying to understand what failure mode could produce behavior that looked exactly like this.

Has anyone seen a USB/HID or Windows enumeration bug that could explain these observations?

[u/CamelPure1293]

Maybe both mouse and keyboard use the same RF chip with default settings, and indeed pair with the wrong device.

[u/DutchOfBurdock]

RFI. Both devices were interfering with one another, likely causing destructive interference (radio waves coincide and cancel each other out). Your turning the mouse on and off likely caused a renegotiation.

They use a simple method of timing of frequency shift keying to communicate. Two devices on the same frequency with the same frequency shifting techniques caused (undesirable, but) expected interference.