Systems and methods for multiple mode voice and data communications using intelligently bridged TDM and packet buses

In a communications system, a first packet network is provided. Packetized data is transferred between the system and one or more packet-based devices. A TDM network is provided, and data is transmitted in frames having slots. Data transmitted via the TDM network includes data for voice communications for telephony devices. The TDM network is selectively coupled to the first packet network and a WAN. A processor and a control bus interface circuit control transfer of packetized data and transmittal of data for voice communications. The processor controls processing of packetized data and data for voice communications. A switch/multiplexer selectively controls providing data to/from particular slots. The processor selectively controls voice communications from telephony devices over the TDM network and packet-based communications over the packet network. Voice communications that stay in a circuit-switched form occur over the TDM network and the WAN.