These were incredibly popular speakers. The shielding in them sucked. It basically turned them into a larger antenna and was able to pick up signals from GSM cellular antennas. So when an incoming call from a tower was searching for your phone and your phone was nearby, the speakers would make a bunch of buzzing sounds for a split second before your phone would ring. 

 Wow, that’s funny lol 

 I think it may have also done it with texts as well. I don't remember.