This is great, I've been looking for just this kind of solution in a small package. I don't always have a GPS antenna drop but I do have a rubidium source in my rack. None of the computers have a 1pps or 10MHz input except for the test equipment so keeping the Windows and Linux boxes synced up is a pain. Since GPS is pretty much never available, I've dropped the GPS receiver from the rack to make room for other stuff. One of the Windows machines runs an NTP server so at least everything displays the same time but without a proper reference clock, the time drifts and trying to do anything at perfect 1Hz intervals is not possible. So many cards or boxes on the market only rely on GPS or IRIG instead of just 10MHz or 1PPS so they are all worthless to me.