The National Science Foundations' OOI cabled observatory (Regional Cabled Array) provides high power (10 kV, 8kW) and bandwidth to >140 instruments on the seafloor and throughout the water column at key study sites: Slope Base near the base of the Cascadia Subduction Zone; Southern Hydrate Ridge, an active methane seep site; Axial Seamount, the most active volcano off the WA-OR coast having erupted in 1998, 2011, and 2015, and the Endurance Array Oregon Offshore and Shelf sites that are some of the most biologically productive areas in the oceans. Power and bandwidth are distributed from fiber optic cables through a total of seven Primary Nodes: one at Slope Base (PN1A), one 10 km south of Southern Hydrate Ridge (PN1B), two at Axial Seamount (PN3A and PN3B), one 1 km south of the Oregon Offshore site (PN1C) and another supporting the Oregon Shelf Site (PN1D). A node (Mid-Plate PN 5A) in the middle of the Juan de Fuca plate is a placeholder node with minimal internal electronics yet available for future network expansion.