A digital answering machine is a device that allows callers to record messages for people when they are not home or not answering the phone. Previously, answering machines used cassette tapes to record messages, and they would have to be manually rewound and advanced to listen to or erase messages. A digital answering machine, however, records messages on random access memory (RAM), which is high-speed memory that is built in to circuitry of the answering machine. There are benefits and downsides to making this switch to digital technology, though most answering machines sold to consumers for home use are now digital, and it can be more difficult to find an answering machine that uses a tape.
One of the immediate downsides to a digital answering machine is that, in general, they offer less recording time than tapes. Most tapes could be recorded for up to an hour, but some digital answering machines only offer about 20 minutes of recording; however, some newer models do have longer recording times. For people who listen to their answering machine messages every day, and then erase them, this will probably not be an issue, but for offices, or those who travel frequently, it might be a small problem if the machine gets full.
There are some other features often found on a digital answering machine that make them quite useful. Multiple voicemail boxes is one of the most popular features; this allows callers to select who they want to leave a message for, and each person in a family or office can then just listen to the messages from their own personal mailbox. A digital answering machine will also often place a date/time stamp on the message so the listener can hear when the call was made.
One feature common across nearly all types of answering machines is the ability to set an outgoing message, and set the number of rings before the machine picks up, usually between two and four rings. Some digital answering machines also offer a "toll saver" feature. This means the owner of the machine can call home from a remote location, and if there are new messages, the machine might only ring twice before it picks up, and if there are no new messages, it might ring four times. This means if the individual is calling home, and the machine doesn't pick up after two or three rings, he or she is free to hang up without paying for the long distance call. Now that nearly everyone has a cell phone, however, this is less of an issue.