This paper discusses how, in recent years, there has been a proliferation of "smart" field devices available for use in process control systems. These devices provide the ability to transmit data to process controllers directly using one of the various standard "field bus" protocols instead of using traditional hard-wired signals such as 4-20mA or 120VAC. This technology can provide operators and managers with a vast array of data with no increase in hardwiring costs and no need for conventional I/O cards. The reduction of conventional I/O cards translates into a decrease in the space requirements for control system enclosures.