WEBVTT - How Digital Answering Machines Work

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<v Speaker 1>Welcome to brain Stuff from how Stuff Works dot com

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<v Speaker 1>where smart Happens, Hi Marshall Brain. It used to be

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<v Speaker 1>that answering machines all used tapes, and some still do,

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<v Speaker 1>but today most answering machines are digital. They use the

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<v Speaker 1>same kind of technology that a CD or MP three

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<v Speaker 1>player uses. The first step in the process is an

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<v Speaker 1>analog to digital converter. This device samples the voice maybe

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<v Speaker 1>eight thousand times per second, and gives a digital value

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<v Speaker 1>to the intensity of each sample. A micro controller stores

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<v Speaker 1>all the samples in low power RAM or flash memory.

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<v Speaker 1>So let's say that a caller leaves a ten second

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<v Speaker 1>message that might translate into eighty thousand bytes of digitized data.

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<v Speaker 1>Those bites are stored at a specific address in RAM.

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<v Speaker 1>To play the message back, the micro controller reads the

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<v Speaker 1>eighty thousand bites from RAM and plays them through a

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<v Speaker 1>digital to analog converter. RAM or flash memory is a

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<v Speaker 1>high speed memory device, so the micro controller can erase

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<v Speaker 1>one of the messages, it can easily move the other

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<v Speaker 1>messages forward into the freed up space, or it can

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<v Speaker 1>store a new message in the blank space. Do you

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<v Speaker 1>have any ideas or suggestions for this podcast? If so,

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<v Speaker 1>Please send me an email at podcast at how stuff

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<v Speaker 1>works dot com. For more on this and thousands of

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<v Speaker 1>other topics, go to how stuff works dot com.