Cell phone jitterbug

I wonder if there are active cell phone jamming technologies out there – a simple electronic device you plug in and operate, say, only during services, that will kill inbound and outbound cell signals. ... Our pastor was even looking into the legality and the plausibility of installing one of those jamming systems theaters were using at the time. It so happened on one particular Sunday, someone's phone went off during communion while the choir was singing “Gift of Finest ...