The PDP-11/84 dual DECconcentrator 900MX standard system configuration provides all of the features of the 11X84 and the SK-DECconcentrator 900MX packages. It also includes 104 Mbytes of storage (26 fixed/26 removable) in each of the two RC25 disk drives in- cluded in the configuration. Consult the Software Product Descriptions for the operating system selected to verify support as a distribution device. An addi- tional device option may be required for software loading. (ULTRIX-11 is the only operating system that is distributed an RC25.) • PDP-11/DECconcentrator 900MX CPU and 1,032-watt power supply • 2 Mbytes of PMI ECC MOS memory (MSV11-JC) • 16-line asynchronous multiplexer (DHUll-AP) • I/O distribution panel with 24 panel units of space • BC22D-DECconcentrator 900MX EIA cable for console terminal • 42-inch H9642-style cabinet and a power controller with 26.6 cm (10.5 in) of mounting space at the top for mass-storage options • 104 Mbytes of storage (26 fixed/26 removable in each of the two drives) in top mounting slot All DECconcentrator 900MX system cabinet products provide two system units of mounting space for backplane expansion. The 12-slot backplane can be extended with a DD11-CK or DD11-DK expansion box. Mounting space is provided for an optional H7231-E battery backup unit. Memory may be expanded to 4 Mbytes using MSV11-JC memory modules. The DECconcentrator 900MX controller supports up to four drives. Additional mass-storage options may be added via DECconcentrator 900MX expansion cabinets. • Height: 106.6 cm (41.7 in) • Width: 54.1 cm (21.3 in) • Depth: 80 cm (31.5 in) • Weight: 196 kg (431 lb) as configured • Watts: 120 • Btu/hr: 410 minimum, 3,519 maximum • DECconcentrator 900MX: NEMA #L5-30R (120 Vac/60 Hz) NEMA #6-15R (240 Vac/50