There are a number of differences between an answering machine and voicemail, though both systems are designed to perform the same basic task. An answering machine is typically a physical device that records messages, either as part of an existing phone or as a separate unit. Voicemail, on the other hand, is a service that allows someone to have messages recorded on a separate server or system, from which the user can then access his or her messages from a remote location. Though designed to accomplish the same goal, an answering machine and voicemail are different in how a person accesses messages, where the messages are stored, and how they can be reached by incoming callers.
One of the major differences between an answering machine and voicemail is how a person is able to access saved messages. Since an answering machine is a physical device typically located with a phone, someone can usually press a button on the device to hear messages. This type of machine can also potentially be accessed through a remote phone line, though this depends on the model of answering machine. Voicemail, on the other hand, can typically be accessed through phones and computers since it is a remote system, which allows someone to more easily hear his or her messages from just about anywhere.
This difference in how the two storage methods are accessed is largely based on how messages are stored in these systems. With an answering machine, a message is recorded and stored within the physical device itself. Voicemail, however, provides a service by which a caller is transferred to a separate system in which messages are received and recorded. This means that recorded messages can be accessed directly from an answering machine, while someone has to access an external system to listen to voicemail messages. Though such a difference between an answering machine and voicemail may be negligible for some people, it can raise concerns for others regarding the security of messages in a voicemail system.
The purpose of both an answering machine and voicemail is to allow someone who is calling to leave a message when no one answers the phone. With an answering machine, as long as no one is on the phone line and no one answers, the call is directed to the machine, which then records a message from the caller. Most answering machines, however, cannot record a message from a caller if someone is on the phone and is unable to answer the incoming call. Voicemail systems, however, typically transfer the incoming call to the voicemail server, allowing callers to leave a message even when the recipient is already on the phone when the second call comes in.