RICST, the Realtime Interferometer Control System Testbed, is a testbed at NASA's JPL where teams are developing a common electronics and software foundation that will form the core of the control system for JPL's various interferometer projects. Important technologies being developed and demonstrated on the RICST testbed include hard real-time multiprocessing, generic interferometer software and hardware architecture, easy reconfigurability, abstract constructs for easy implementation of control loops and servos, and highly configurable telemetry streams. The basic hardware and software architecture developed by RICST can be applied to virtually any interferometer based on the combiner-collector architecture. The RICST project began in May 1996 and has been delivering control system 'increments' every few months since that time. Each increment adds new end-to-end functionality. White-light fringe tracking has been demonstrated in the lab already; the delivery of a fully operational testbed is scheduled for the end of April. Future enhancements will add support for a wide array of calibration, sequencing, and other support functions. RICST deliveries include support software, such as a graphical user interface and a prototype spacecraft bus interface, as well as the embedded software needed to run the instrument. The RICST program will make final deliveries to its various customers in 2000, after which the RICST testbed facility will continue on in support of the SIM mission.