Welcome to brain Stuff from how Stuff Works dot com where smart Happens, Hi Marshall Brain. It used to be that answering machines all used tapes, and some still do, but today most answering machines are digital. They use the same kind of technology that a CD or MP three player uses. The first step in the process is an analog to digital converter. This device samples the voice maybe eight thousand times per second, and gives a digital value
to the intensity of each sample. A micro controller stores all the samples in low power RAM or flash memory. So let's say that a caller leaves a ten second message that might translate into eighty thousand bytes of digitized data. Those bites are stored at a specific address in RAM. To play the message back, the micro controller reads the eighty thousand bites from RAM and plays them through a
digital to analog converter. RAM or flash memory is a high speed memory device, so the micro controller can erase one of the messages, it can easily move the other messages forward into the freed up space, or it can store a new message in the blank space. Do you have any ideas or suggestions for this podcast? If so, Please send me an email at podcast at how stuff works dot com. For more on this and thousands of other topics, go to how stuff works dot com.