On Fri, Dec 23, 2011 at 5:51 PM, Mike S <[email protected]> wrote: > At 01:58 PM 12/23/2011, Chris Albertson wrote... > >> But there is no hop of doing uS >> level over the gigabit either net. > > > IEEE 1588.
Seem 1588 can work at the sub uS level but actual real-work software on Linux works at the "tens of uS" level. The limiting factor is the hardware's ability to time stamp eithernet packets. If you have special hardware you can get to sub-uS but not using PTPd on Linux or BSD. Linux's and BSD's time stamper for the PPS interface works better (less jitter) then its time stamper for Ethernet. In a standard Cat-5 cable there are 8 wires in 4 pair. Ethernet only uses 2 pair. I simply used a "spare" pair for a pulse. The parts required cost under $5 assuming you have tools to build cables already or old cables you can hack. -- Chris Albertson Redondo Beach, California _______________________________________________ questions mailing list [email protected] http://lists.ntp.org/listinfo/questions
