This paper presents an extension to the Carrier Sense Multiple Access with Deterministic Collision Resolution (CSMA/DCR) protocol that is highly attractive for use in real--time (RT), fault--tolerant, bus--connected Local Area Network (LAN) systems. CSMA/DCR is one of the few major RT bus LAN protocols, striking a good balance between the CSMA/CD protocol with weakly predictable timing behavior, and the TDMA protocol that has a tightly bounded worst--case delay but is inflexible. We learned that the ordinary CSMA/DCR and several other LAN protocols are not very robust in that the protocols lose their real--time delivery properties when various types of faults occur. The extension to the CSMA/DCR protocol that we present in this paper maintains real--time delivery properties in the presence of multiple faults. Since robustness is implemented at the Medium Access Control (MAC) layer level, this version of CSMA/DCR is capable of delivering frames in bounded time when permanent and transient faults occur, thereby providing to the upper Logical Link Control (LLC) layer a reliable RT service.