The crude tech of mobile phones compared to what we have today is probably just a product of the era when they were created. I imagine they haven't changed that much since they were first coded... in the late 90's. Scary that, huh? :)
Are there Polly Parrots still kicking around in game? They were just a fun toy, there's a way to turn them on and off (possibly "shake" or "squeeze", honestly can't remember). When they're on they record everything that's said around them (should record your location while you're carrying it) and at random intervals they repeat a random phrase they've recorded.
They have a limited memory, when that's reached each new phrase bumps off the oldest one. Anything they record is anonymous.
Much fun to be had hiding them in locations or planting them on people. I think most of them got trashed or turned off after the initial "fun". Really not much use as a bugging device to be honest, but they have code (possibly not great, it was a quickly hashed together trinket) that handles recording while hidden or carried, etc, so they could be adapted for bugging.