Voice Profile for Internet Mail (VPIM) is an Internet Engineering Task Force (IETF) specification that defines a unified way of transmitting voice mail and fax messages over the Internet. Voice profile for Internet mail (VPIM) uses e-mail systems that support Multipurpose Internet Mail Extensions (MIME) and Simple Mail Transfer Protocol Service Extensions (ESMTP) standards for Internet messaging. VPIM can also be deployed over corporate intranets for integrated business messaging solutions. VPIM includes a proposed directory service that enables lookup of routable addresses and includes a mapping specification to support interoperability with other voice messaging systems.
VPIM defines the mechanisms by which voice mail and fax messages can be exchanged between Simple Mail Transfer Protocol (SMTP) mail servers on a TCP/IP internetwork. However, VPIM leaves open the way in which specific mail clients interface with these SMTP servers to send and receive voice and fax messages, which will initially be accomplished by implementing VPIM helper applications. VPIM is implemented as a MIME profile, which allows voice and fax information to be encoded using any SMTP mail server that supports MIME. You can implement VPIM by running additional VPIM software on existing SMTP mail servers or by installing VPIM-SMTP gateways on the TCP/IP internetwork. VPIM gateways support messaging between telephones, cell phones, fax machines, pagers, and computers. VPIM will be able to use Lightweight Directory Access Protocol (LDAP) or X.500 based directories for white pages lookup to address messages to users.
VPIM is supported by the popular UNIX mail forwarder software called Sendmail; other vendors are also implementing VPIM. The current standard, VPIM v2, can be found in Request for Comments (RFC) 2421, and VPIM v3 is under development.