These documents are drafts and will change as the various TIC subcommittees meet and refine the plans. The ANSS-MA will follow the standards outlined by these committees. I'm sure Ray Buland has stacks of them. I've seen a report by David Simpson in 1988 with something along these lines. More recently, Mitch Withers used a similar diagram in the model of Mid-America regional operations and I borrowed some of his nomenclature for this draft.
Nothing here is cast in stone.
First, some definitions and functionality. The red and black circles indicate seismic stations. They may be any type of station - national, regional, or urban. Red indicates ANSS supported or funded stations, black indicates non-ANSS supported. The red lines indicate a communications link.