Abstract: An opto-coupler interface provides secure control over the ability of a remote network (Internet) user to access a local user workstation. The interface is installed as an auxiliary unit between the external network and the local user's workstation connection to its associated local area network. Once installed, the opto-coupler based connectivity interface allows a computer end user to selectively provide a communication path between the end user's workstation and an external data communication network, only during the time that the user wishes to be connected to the network. In the absence of this switched connection, the opto-coupler is turned off, thereby securely severing the external access communication link and thereby preventing external data communication network access to either the end user or a local network with which the end user's workstation is normally connected.