> refclock PPS /dev/pps0 refid GPS > refclock PPS /dev/pps1 refid PPS > refclock PPS /dev/pps2 refid PPS Check the documentation. (It maybe buggy too.) My guess is that you are supposed to use refclock PPS(0) /dev/pps0 refid GPS refclock PPS(1) /dev/pps1 refid PPS refclock PPS(2) /dev/pps2 refid PPS Like ntpq -p shows you. -- These are my opinions. I hate spam.