more more (Score 2, Informative)

http://www.sciamdigital.com/index.cfm?fa=Products.ViewIssuePreview&ARTICLEID_CHAR=253EE806-FA7B-4693-8F1D-BDBB1E68AAF is an article i wrote many moons ago for scientific american on these optical telegraph networks more info still, in this book: http://spinroot.com/gerard/hist.html