I haven't heard any mention of that in ages.  NTPsec dropped that driver (and
many others).

Which brand of ntpd are you using?  What version?  What distro are you using?

If you are using the classic/Mills ntp package, it's driver 18.  "ACTS" is the
magic word.  I don't know if your distro was built with that driver.  If not,
you will have to build from source.  (No big deal.)

Here is the doc for that driver:
https://docstore.mik.ua/ntp/driver18.html
There are many copies out there.  This was the top of Google's list.

Plan B would be to use ntpd's shared memory interface.  That's what gpsd uses.
The general idea is that you do whatever it takes to get a time offset, then
drop it into a shared memory slot.  ntpd polls that slot.

If you have detailed NTP questions, we should probably take it off-list.

When you get it working, we expect data.  Extra credit for a pretty graph.

What modem are you using?

How did you decide to go with modems rather than NTP over the internet?

--
These are my opinions.  I hate spam.

On 8/9/22 22:16, halmurray at sonic.net (Hal Murray) wrote:

I believe Hal is incorrect. NTPsec has not removed this driver. It's the
"modem" driver.

If you're using Debian, it is not compiled into the ntpsec package (per
my choice, as I'm the maintainer). But it does work if you build from
source. Or at least it did the last time I played with it, a couple
years ago:
https://lists.ntpsec.org/pipermail/devel/2020-September/009537.html

The most relevant git commit was to add this example config snippet:

refclock modem mode 1 minpoll 12 maxpoll 17
phone ATDT13034944774 # NIST

I hope that helps.

If you're doing this for any reason other than "because I can" fun,
you're probably doing it wrong. Use GPS or the Internet for production
stuff. But have fun!

--
Richard

Richard,

I would respectfully disagree with the last statement, "If you are doing
this for an reason other than 'because I can" fun, you're probably doing it
wrong."  IMHO, the time community should diversify as many sources as
possible that don't rely on GPS or the Internet.

I think that we should be using as many sources as possible so that NTP has
as much data as possible to select the "goodchimer" from.  Yes, using a
modem for PTP or 1PPS might not be the best option but modems and LFR are
still good diverse options.

Thank you for your thoughts
Todd

On Tue, Sep 13, 2022 at 1:53 PM Richard Laager via time-nuts <
time-nuts@lists.febo.com> wrote: