The IBM System Storage DS4000 series of high-performance, high-availability, business-critical storage solutions now includes a 4 Gbps-capable, dc-powered storage expansion unit that is especially well suited for telco industry applications.IBM System Storage DS4000 EXP810 Storage Expansion Unit Model 81-DC is a NEBS-3-compliant storage expansion unit designed to be powered from a -48 V dc telco industry-standard power source.EXP810 Model 81-DC comes in a compact 3U, 16-bay disk enclosure and has a physical storage capacity of up to 4.8 TB per enclosure (using 300 GB fiber channel E-DDMs), or up to 8 TB per enclosure (using 500 GB SATA E-DDMs).