These DECbridge 90FL product variations feature a unique, expandable open card - cage design packaged in a 42-inch shielded cabinet. The base configurations in- clude the 1 DECbridge 90FL and either 1 or 2 Mbytes of memory. The system building block product also includes a 16-line asynchronous multiplexer. All product variations offer 10.5 inches of mounting space in the top of the cabinet for device options. At the DECbridge 90FL rear of the cabinet there is a large IODP bulkhead that provides 24 panel units for option connection. These configurations are gen- erally used to create large DECbridge 90FL systems that include many disks, magnetic tapes, and/or many (more than 16) terminals or communication lines.