Please find enclosed a draft 4 of the Touchstone 2.0 specification (markup and "clean" copies). This draft makes minor editorial corrections as suggested by Bob Ross. It also clarifies the usage of noise parameters as proposed by Radek Biernacki and Bob Ross. Comments are welcome. The documents will be discussed at the next Ad Hoc Interconnect meeting. - MM <<touchstone2_review_draft4.pdf>> <<touchstone2_review_draft4_markup.pdf>>