2.4ghz wireless, device differentiation

[Rick Law]

I have two identical 2.4ghz non-bluetooth wireless keyboard+mouse, each came with a USB plug.  While both look identical, the USB plug that came with the device only works with that specific device.  Out of curiosity, how do the two seemingly identical devices differentiate themselves?

Does the 400Mhz wireless devices work the same way or use a different scheme?

Thanks!

[ataradov]

Typically they just use a plain text serial number. More recent device may involve some basic encryption/obfuscation.

[technix]

The 2.4GHz/433MHz number indicated a fairly wide frequency band, which is often subdivided into narrower frequency bands or channels within. Those devices can operate on different channels within that same general band.

Secondly, wireless keyboards and mice often come with some kind of identifier or addressing scheme in their protocol. The receiver will ignore sources from a wrong address. Some better models even have some basic encryption which a wrong receiver won’t be able to decrypt properly.