I went through a Collins style PTO and documented what I found. Al was kind enough to put it on the R-390A disk in the 'Tutorials' area of the 'Refenence' section. Here's a direct link: http://www.r-390a.net/R390A_My_Collins_PTO_Observations.pdf Or you can start at the FAQ page: http://www.r-390a.net Regards, Larry