Abstract: Systems and methods for a radio communications device supporting LTE cellular communications. A device includes a data interface configured to exchange modem control commands and audio data with an LTE cellular modem and a telephone interface configured to provide a two-wire analog telephone interface for connection to a telephone device. A controller control signals provided via the telephone interface to manage voice call operations with the telephone device; exchange digital voice data corresponding to voice signals exchanged with the telephone device via the telephone interface; exchange control information via the data interface to establish and manage a voice over LTE cellular call; and exchange the digital voice data via the voice over LTE cellular call via the LTE cellular modem.