Cell phone receiving RF interference question. Something strange happened in my calculus class in the middle of a lecture last week. A student's phone suddenly was connected to a live telephone conversation without the student pressing a button or touching the screen with the phone sitting on her desk the whole time before this happened and the whole room could hear it. There were two people talking on the phone to each other, so it was certainly not a butt dial. So it appears that the phone actually picked up another phone call accidently. If my community college has 40,000 students and if say 2,000 students are in the school on a Monday at 2PM, and if say 50 students in the school are talking on the cell phone at the same time, is it possible that the network could be overwhelmed and accidently pick up nearby calls? Is the audio amp in a cell phone even turned on when a phone is not in a call? I don't think it is, so it definitely received a call. I don't think having the audio amp in a cell phone turned on when the phone is not in a call would be a good idea because then the audio amp would demodulate radio interference. Actually, I have heard morse code beeping on my phone with my phone not in a call when I was flying out of O'hare I could heard the ORD morse identifier (--- .-. -..)quitely on the phone speaker even though the phone was not in a call. So it appears that if the signal is close enough, like you are flying above O'hare airport, then an audio amp is not needed and the speakers with the semiconductor components in the cell phone will demodulate radio interference into audio very quietly. (This is the first time I ever heard this because there were only 25 passengers on the plane since the plane was flying from Chicago to a small city when I was vistiting my divorced parents who moved to different parts of the U.S. and it was dead silent on the plane except for the jet engines and when I looked at the time on my phone if I held it close to my ear I could hear morse code beeping).