Provided is an apparatus for protecting a multi-function product from
surge voltage, the multi-function product including a public telephone
network connection unit which receives one of a ring signal, a voice
signal, and a fax signal and transmits the signal via first and second
signal lines and an external apparatus connection unit which is connected
to an external apparatus, receives a data signal from the external
apparatus, and transmits the data signal via the first and second signal
lines, the apparatus including: a first surge voltage cut off device
having first and second terminals, wherein the first terminal is
connected to the first signal line and the second terminal is connected
to the second signal line; a second surge voltage cut off device having
first and second terminals, wherein the first terminal is connected to
the first signal line; a switching unit having a first terminal connected
to the second signal line and a second terminal connected to one of a
first contact point connected to the external apparatus connection unit
and a second contact point connected to the second terminal of the second
surge voltage cut off device; and a control unit which senses a signal
received from the multi-function product and controls the second terminal
of the switching unit to be switched between one of the first contact
point and the second contact point.