Voicemail (also known as voice-mail, VMS, or message bank) is a centralized system of stored telephone messages that can be retrieved by the recipient at a later time. The term is also used more broadly to denote any system of conveying a stored telecommunications voice message, including using an answering machine. Most cell phones have voicemail as a basic feature, and many land line phones and corporate PBXs have their own voicemail options.
Voicemail systems are designed to convey a recorded audio message to a recipient. To do so they contain a user interface to select, play, and manage messages; a delivery method to either play or otherwise deliver the message; and a notification ability to inform the user of a waiting message. Most systems use phone-networks, either cellular or land-line based, as the conduit for all of these functions. Some systems may use multiple telecommunications methods, permitting recipients and callers to retrieve or leave messages through multiple methods.
Simple voicemail functions as a remote answering machine using a touch-tone as the user interface. More complicated systems may use other input devices such as voice or a computer interface. Simpler voicemail systems may play the audio message through the phone, while more advanced systems may have alternative delivery methods, including email or text message delivery, message transfer and forwarding options, and multiple mailboxes.
Notification methods also vary based on the voicemail system. Simple systems may not provide active notification at all, instead requiring the recipient to check with the system, while others may provide an indication that messages are waiting. Almost all modern voicemail systems use digital storage and are typically stored on computer storage devices.
By the year 2000, voicemail had become a ubiquitous feature on phone systems serving companies, cellular and residential subscribers. Cellular and residential voicemail continue today in their previous form, primarily simple telephone answering. Email became the prevalent messaging system, email servers and software became quite reliable, and virtually all office workers were equipped with multimedia desktop PCs.