One modern version happened at work a few years ago. Every time our Little boss, as opposed to the big boss who we could not have done this to went out of his cubicle. One of the guys would go in there and remove the microphone part of the telephone from the handset. He would come back, the phone would ring and he would answer, the person at the other end could hear nothing. This head would pop up and down from his cubicle shouting there's something wrong with this $#%#^* phone again. This went on many times during the course of a week or two we stopped when he called the phone repair people. To this day he is unaware of what was really going on. If you try this and get fired, don't blame me. JohnB. It is even easier these days with the plug in handsets and a piece of Scotch tape.