Editing Answering machine (section)

== Pure voice operation ==
In case of voice-only environments any accepted call can be directly handed over to a TAD, which may be preemptively superseded by a human-operated handset, taking control by simply going off-hook itself, forcing the TAD (back) on-hook. Voice signals may simply be captured to and replayed from analogue media (mostly tapes), but later TADs shifted to digital storage, with all of its convenience for compression and handling, for both the greeting and for the recorded messages.

=== Greeting message ===
[[File:OutgoingMessageTape.jpg|thumb|upright=1.1|right|An endless-loop outgoing message tape used in dual-cassette-based answering machines]]

Most modern answering machines have a system for greeting. The owner may record a message that will be played back to the caller, or an automatic message will be played if the owner does not record one. This holds especially for the TADs with digitally stored greeting messages or for earlier machines (before the rise of [[microcassette]]s) with a special endless loop tape, separate from a second cassette, dedicated to recording.

There have been answer-only devices with no recording capabilities, where the greeting message had to inform callers of a state of current unattainability, or e.g. about availability hours. In recording TADs the greeting usually contains an invitation to leave a message "after the beep".

=== Recording messages ===
[[File:Autoanswer-mikrokassete.JPG|thumb|An answering machine that uses a [[microcassette]] to record messages]]

On a dual-cassette answerphone, there is an outgoing cassette, which after the specified number of rings plays a pre-recorded message to the caller. Once the message is complete, the outgoing cassette stops and the incoming cassette starts recording the caller's message, and then stops when the caller hangs up.  The incoming cassette remains stopped at the end of the last recorded message, so it is ready to start recording another message, from another call, immediately on demand.  However, the incoming message cassette must be rewound before the stored messages can be played back; typically there is a single button to play messages which when pressed causes the machine to automatically first rewind the incoming message cassette and then start playback.  Some machines will keep track of the position of the end of the last message that has already been played back and only rewind to that point in order to only play back new messages, unless the user explicitly rewinds the tape further and then starts playback.

Single-cassette answering machines contain the outgoing message at the beginning of the tape and incoming messages on the remaining space. They first play the announcement, then fast-forward to the next available space for recording, then record the caller's message. If there are many previous messages, fast-forwarding through them can cause a significant delay. This delay is taken care of by playing back a beep to the caller, when the TAD is ready to record. This beep is often referred to in the greeting message, requesting that the caller leave a message "after the beep".

TADs with digital storage for the recorded messages do not show this delay, of course.

=== Remote control ===
A TAD may offer a remote control facility, whereby the answerphone owner can ring the home number and, by entering a code on the remote telephone's keypad, can listen to recorded messages, or delete them, even when away from home.

Many devices offer a "toll-saver" function for this purpose. Thereby the machine increases the number of rings after which it answers the call (typically by two, resulting in four rings), if no unread messages are currently stored, but answers after the set number of rings (usually two) if there are unread messages. This allows the owner to find out whether there are messages waiting; if there are none, the owner can hang up the phone on the, e.g., third ring without incurring a call charge.

Some machines also allow themselves to be remotely activated, if they have been switched off, by calling and letting the phone ring a certain large number of times (usually 10-15). Some service providers abandon calls already after a smaller number of rings, making remote activation impossible.

In the early days of  TADs a special transmitter for [[dual-tone multi-frequency signaling|DTMF tones]] (dual-tone multi-frequency signalling) was regionally required for remote control, since the formerly employed [[pulse dialling]] is not apt to convey appropriate signalling along an active connection, and the dual-tone multi-frequency signalling was implemented stepwise.

[[File:GE ProSeries 29980A answering system.jpg|alt=A General Electric corded telephone with a built-in microcassette answering machine|thumb|A General Electric corded telephone with a built-in microcassette answering machine]]