Introduction The Cisco Foreign Exchange Office (FXO) interface is an RJ-11 connector that allows an analog connection to be directed at the public switched telephone network's (PSTN's) central office or to a station interface on a private branch exchange (PBX). The FXO sits on the switch end of the connection. It plugs directly into the line side of the switch so the switch thinks the FXO interface is a telephone. Note: The FXO Voice Interface Card (VIC) is not the same as a Foreign Exchange Station (FXS) card and therefore does not provide dial tone. Do not plug a telephone set to the FXO VIC. Requirements There are no specific requirements for this document. Components Used This document is not restricted to specific software and hardware versions.