Abstract: A network-field interface, termed an NFI, is intended for digitally interfacing at least one host computer on a network to at least one field device. The network operates with a predetermined communications protocol including READ and WRITE services. The NFI comprises I/O ports for connection to the field devices, a modem to facilitate communication between the network and the interface, a CPU, volatile and non-volatile memory accessible to both the modem and the CPU, and program modules resident in the memory. The program modules are executable by the CPU to map the READ and WRITE services of the network onto the NFI's I/O ports. In this way the host computer is able to READ and WRITE directly to the I/O ports through the modem.