ENUM (RFC 2916) is the Internet Engineering Task Force (IETF)
protocol that will assist in the convergence of the
Public Switched Telephone Network (
PSTN) and the
IP network; it is the mapping of a telephone number from
the PSTN to
Internet services telephone number in,
URL out. ENUM was developed as a solution to the question
of how to find services on the Internet using only a telephone number, and how
telephones, which have an input mechanism limited to twelve keys on a keypad,
can be used to access Internet services.