[wowczarek]

Remember those little LED keychains for your "mobile phone" that would magically light up when taking/making calls and sending/receiving texts?

[zoklet-enjoyer]

I don't remember that, but I do remember my speakers buzzing just before a call or text came through.

[b00ty4breakfast]

they still do that, but I think that this is RFI from the processor rather than a deliberate rf transmission

[thenthenthen]

These stopped working since 2G, since it uses radically less power. Altho I did recall seeing some fancy phone cases with blinkies on 3G… never could replicate it sadly. I guess with a lot of joule thief/stepup circuits it might work…