The authors describe an optical fiber link that is used in conjunction with the CERN host interface family to connect high-performance VAXes to VMEbus or FASTBUS over distances up to 1000 m. The modular construction allows other permutations, including VAX/VAX, FASTBUS/FASTBUS, VMEbus/VMEbus, or FASTBUS/VMEbus connections, over similar distances. The link comprises two identical optical data interconnects (ODI) connected by two unidirectional multimode fibers. The ODI at each end of the link can be connected to any device conforming to the DRB32 user interface specification. The authors discuss the operation of an ODI, the testing of the optical link, and present and future ODI implementations.