Systems for voice and data communications having TDM and packet buses and telephony station cards including voltage generators

A communication system coupled to a wide area communication network comprising a plurality of network resources, the communication system providing voice and data communications in an office and comprising:

• at least a first packet bus coupled to one or more packet-based devices and adapted for transferring packetized data to and from the system;
• at least one time division multiplex (TDM) bus coupled to one or more telephony devices and selectively coupled to the first packet bus and the wide area communication network;
• a processor;
• wherein the processor selectively controls voice communications from the one or more telephony devices over the TDM bus and packet-based communications over the first packet bus, wherein voice communications that stay in a circuit-switched form in the communication system occur over the TDM bus and the wide area communication network, and wherein packet-based communications are selectively coupled to the wide area communications network via the TDM bus;
• wherein the communication system includes one or more station cards for interfacing to one or more of the telephony devices, wherein at least one of the station cards comprises:
• an input for receiving an input voltage of a first voltage level from an external power supply;
• a voltage generation circuit on the station card, wherein the voltage generation circuit generates one or more control voltages/signals of at least a second voltage level different from the first voltage level for controlling the one or more telephony devices from the input voltage;
• and
• one or more interface circuits receiving the one or more control voltages/signals, wherein the one or more interface circuits are coupled to the one or more telephony devices.