Abstract: A device that provides a gateway between a public switching telephone network and a gateway device comprises a controller interface including telephony circuitry, power circuitry, and a master cellular phone circuit. The controller is connected to at least one public switching network. The controller interface further includes a plurality of cartridge slots connected to the telephony circuitry and the master cellular phone circuitry, wherein the telephony circuitry links the master cellular phone circuitry to the public switching telephone network. The device further includes a plurality of transceiver cartridges removeably connected to the cartridge slots of the controller interface. The transceiver cartridges are operably configured to wirelessly link the master cellular phone circuitry to the cellular networks. Additionally, the controller interface circuitry is operably configured to switch between land line telephone network and the plurality of cellular networks based on preset conditions.