Patent ID: 7463726

Claim:
A system having a dual system interface apparatus for allowing a Public Switched Telephone Network [PSTN] telephony system and a cellular wireless telephony system to be simultaneously operable while connected to the same residential wiring wherein the apparatus includes automatic best economic session logic and emergency dialing logic comprising: a primary and secondary circuit transposer placed between a main PSTN line and each Plain Old Telephone service [POTs] device attached to said main PSTN line such that said primary circuit of each of said POTs devices appears on said secondary circuit of said main PSTN line; a first port of a dual system interface attached to said primary circuit of said main PSTN line; a second port of said dual system interface attached to said secondary circuit of said main PSTN line; a cellular wireless telephony device to connected to a third port of said dual system interface, said cellular wireless telephony device communicating with a wireless telephony system such that each of said POTs devices and said cellular wireless telephony device are simultaneously operable; and the apparatus having stored therein one or more machine instructions for routing emergency messages according to the emergency dialing logic.