A system for connecting a portable information equipment and an extension
telephone, comprises: an extension telephone connecting device for
connecting the portable information equipment to an extension telephone
system after authentication through a virtual private network (VPN); and
a Voice over Internet Protocol (VoIP) connecting device for connecting
the portable information equipment connected to the extension telephone
system to the extension telephone connected to the extension telephone
system by VoIP. This system enables a temporary staff to make a call from
outside to an extension telephone system in a dispatched company while
maintaining security.