[time-nuts] ``direct'' RS-232 vs. RS-232 via USB vs. PPS decoding cards

[Gary E. Miller]

Yo Chris!

On Wed, 15 Feb 2017 23:55:02 -0800
Chris Albertson <albertson.chris at gmail.com> wrote:

> On Wed, Feb 15, 2017 at 11:48 PM, Chris Albertson
> <albertson.chris at gmail.com> wrote:
> > On Wed, Feb 15, 2017 at 10:30 PM, Ruslan Nabioullin
> > <rnabioullin at gmail.com> wrote:  
> >> On 02/15/2017 01:17 PM, Chris Albertson wrote:  
> >>>
> >>> Why set up a dedicated NTP server if you only have two computers
> >>> that will use it?    Your server will be accurate to a few
> >>> microseconds but your two computers will only by good to a few
> >>> milliseconds because ethernet is not nearly as good as PPS.  
> >>
> >>
> >> Well Ethernet can be *extremely* accurate if PTP is used (a
> >> whitepaper specifies <= 100 ns accuracy if the LAN is optimized
> >> for it).  
> 
> But PTP requires special hardware.   You may not have this.

No, PTP works optimally with special hardware, it can work with any
ethernet port.

I will give you that software mode PTP is no more accurate than 
plain NTPv4.

RGDS
GARY
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Gary E. Miller Rellim 109 NW Wilmington Ave., Suite E, Bend, OR 97703
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