How Do Answering Machines Work?by Stephen LilleyUpdated September 12, 2017
An answering machine is a device designed to insure that a person never misses a phone call, even when they aren't near the phone. When a person calls your land-line phone and you are unable to pick up, the answering machine takes over and plays a pre-recorded message alerting the caller to your absence. The answering machine then begins to record, allowing the caller to leave you a message that can be played back later. Once you've heard the message it can then be deleted or erased to make room for more messages. Most land-line phones purchased today have a digital answering machine built in.
Digital Answering Machines
The most common type of answering machine found today is the digital answering machine. This type of answering machine will record a caller's message to a digital computer file. The computer file is then saved to an internal memory device. Once played, the message can be kept in the machine's internal memory until deemed unnecessary. At this point it can be deleted, making room for more callers to leave more messages.
Tape Answering Machines
Early answering machines recorded a caller's message to a small cassette tape. Each tape had two sides and could only hold a finite length of audio. To listen to messages a person would have to physically rewind the tape to the beginning and play the message, making sure to place the tape in the right position afterward so as not to accidentally record over important information. When calls were deemed unnecessary a person could simply rewind the tape to the beginning and allow the machine to record over old messages.