An input/output register to FASTBUS interface (IORFI) has been designed which provides an inexpensive and simple means to connect a computer to a FASTBUS backplane segment. The FASTBUS backplane interface is built on a single width FASTBUS module. It is connected to a computer by two 16-bit parallel input registers and two 16-bit parallel output registers, which makes the interface computer-non-specific. This paper describes the operational characteristics of this interface, its advantages, limitations, and briefly, the uses to which it has been put.