Instructions

1  Purchase a cell phone jammer, which will stop your cell phone from sending and receiving signals. Top-of-the-line jammers block out cell phones in an estimated 100-foot radius from sending signals to a cell phone tower. More modest jamming devices cover a 15-foot radius.
2 Jam the signal by turning the device on. Some jamming devices utilize a flip feature, while with others you just click a button. The jamming device is about the same size or a little smaller than a standard cell phone. Also, ensure that the jamming device is close by to your cell phone for it to work properly.
3 Turn off the jammer when you are done using it. This is important because there is the potential to jam and interfere with other radio signals in immediate area.(from eHow)