A field device interface module includes a connector, a plurality of terminals, a protocol interface module, a controller and a power supply module. The connector is configured to operably couple to a computer. The terminals are operably coupleable to a field device. The protocol interface module is coupled to the plurality of terminals and configured to generate signals in accordance with a process communication protocol. A power supply module is coupled to the plurality of terminals. The controller is coupled to the protocol interface module and to the power supply module and is configured to measure a voltage across the plurality of terminals and selectively cause the power supply module to provide power to the field device.