Least cost routing device for separate connection into telephone line

A device interconnects within the phone line coming from a first phone and routes telephone calls along a least cost route originating from the first telephone to a second telephone via the network. A housing forms an enclosure and has a first jack for interconnection to the phone side of the phone line and a second jack for interconnection to the network side of the phone line. The housing forms an enclosure which includes a switch for disconnecting the first phone from the network. The device generates a source of current through the switch to the first phone corresponding to the amount of current provided by the phone network. A database stores billing rate parameters for determining various communication paths of different carriers based on parameters such as the time and date of the call. Phone calls from the first phone are detected and stored. The database is addressed and a plurality of communication switch paths are identified as well as the cost rate of each path. The cost rates for each identified path are compared to determine a least cost route for the call. The device generates a number sequence corresponding to a desired carrier so that the dialed call is routed through the second jack and phone line to the selected communication path and carrier so as to establish a switched connection between the first and second phones.