[ntp:questions] Re: PPS kit and Spectracom TTS240rb

abrown at mlp.com abrown at mlp.com
Thu Jul 13 16:57:14 UTC 2006


Thanks for the details. This was right on the money. I had another chat
with the vendor and after several iterations of possible configurations
he provided the " ... you can upgrade to this new model (the 9238) that
has all of the functionality you need under the cover, PLUS it uses
ntpv4 compliant code."

I'll be sure to tap RedHat about the PPS kit for ES4, but they're
typical answer for such requests is wait for  the next release. I'll
see what I can do with PPSkit lite if that is the case.

Once again, thanks to all that were invloved.


mike wrote:
> abrown at mlp.com wrote:
> > Ulrich Windl wrote:
> >
> >>abrown at mlp.com writes:
> >>
> >>
> >>>Fellow techs,
> >>>
> >>>Thanks for tuning into my issue of the day. I need to achieve 2 things.
> >>>The first is to obtain and install the PPS kit onto Spectracom's
> >>>TTS240rb. I spoke with the support folks a Spectracom and they
> >>>suggested I post here. The second is to install the PPS kernel
> >>>components on a RedHat ES 4 system running 2.6.9-XX.
> >>>
> <snip>
> > Regardless, after running the test scripts, it appeared that my kernel
> > and hardware could  in fact get to within a millisecond. My next
> > question was, how do I get that improvement into my environment. The
> > answer from my vendor was 2 part: 1. get a PPS kit for my Spectracom
> > time server
>   I think you may have misunderstood your vendor. I had a look at the
> Spectracom data sheet and your device is a complete ntp server with the
> extra PPS + other time code output. You do not need, and could not apply
> any modifications to the propriety Server code in the box.
>   As for a PPS Kit for your linux distrib, I suggest you talk to
> Redhat. They may have an implementation ready to go, else you could
> tailor  PPSkit-light yourself.
> http://www.kernel.org/pub/linux/daemons/ntp/pps/
>    from Spectracoms data sheet:
>   Type                           Connector
>   Ethernet 10/100 BaseT          RJ45 (auto sensing)
>   Two RS-232 Serial Comm         DB9 female
>   Two RS-485 Once-per-second     3.81mm Terminal Block
>   IRIG B/E AM/TTL                BNC
>   1PPS, Pulse-per-second         BNC
>   so you will need hardware to convert PPS (or IRIG ) to rs232 input to
> your server. THese outputs usually put out low voltage signals not
> suitable for direct connect to PC interfaces.
>   10 MHz                         BNC
>   Three Alarm/Programmable Timer 3.81mm Terminal Block
>    So using just the NTP server over ethernet  you should be seeing sub
> millisecond accuracy. To get better you should check try the Type 4
> refclock driver which states it supports all known Spectracom servers
> over the rs232 interface, where I guess there is proprierty time code
> though I could not down load the manual to check what formats are available.
>    I could not see a generic IRIG driver available. There must be one
> somewhere.
> and 2. get the appropriate PPS implementation for my client
> > systems. In looking around the internet, I've found a few postings that
> > led me to believe that people have this working for other linux
> > implementations that were NTPv4 and various kernel revs.
> > 
> > Is this making sense? Thanks for your time.
> > 
> > Allen
> >

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