Hello; I’m wondering if someone would be willing to assist me in getting NTP to reference time from NIST (Colorado) or NRC (Ottawa) via a dial-up modem. Either as a primary source, or as a failover in case the GNSS signal is lost. I have several commercial GPS-referenced clocks operating as primary NTP servers, however also employ a few Raspberry Pis as experimental boxes so that I can trial different GNSS antennas, constellation combinations, etc. I would like to get one of the Pis to use a hardware USB modem to dial out every so often to obtain the time via the telephone network. Right now the Pi in question has a GNSS RTC board on it and is working well in that capacity. I’d like to add the modem in, and this is where I’ve run into a wall. Is there anyone who’s done this and would be able to help me get this Pi up and running? The modem is connected and the Pi can see it, but NTP doesn’t seem to be dialing out. I think I’m missing a config file or two. You can contact me off-list if this is too off-topic for the group. Thanks, Avro avro125@gmail.com

I think NIST still runs a dialup time server after all these years: https://www.nist.gov/pml/time-and-frequency-division/time-distribution/automated-computer-time-service-acts On Tue, Aug 9, 2022 at 5:56 PM Avro125 via time-nuts < time-nuts@lists.febo.com> wrote: > Hello; > > > > I’m wondering if someone would be willing to assist me in getting NTP to > reference time from NIST (Colorado) or NRC (Ottawa) via a dial-up modem. > Either as a primary source, or as a failover in case the GNSS signal is > lost. > > > > I have several commercial GPS-referenced clocks operating as primary NTP > servers, however also employ a few Raspberry Pis as experimental boxes so > that I can trial different GNSS antennas, constellation combinations, etc. > I would like to get one of the Pis to use a hardware USB modem to dial out > every so often to obtain the time via the telephone network. > > > > Right now the Pi in question has a GNSS RTC board on it and is working well > in that capacity. I’d like to add the modem in, and this is where I’ve run > into a wall. > > > > Is there anyone who’s done this and would be able to help me get this Pi up > and running? The modem is connected and the Pi can see it, but NTP doesn’t > seem to be dialing out. I think I’m missing a config file or two. > > > > You can contact me off-list if this is too off-topic for the group. > > > > Thanks, > > > > Avro > > avro125@gmail.com > _______________________________________________ > time-nuts mailing list -- time-nuts@lists.febo.com > To unsubscribe send an email to time-nuts-leave@lists.febo.com

Dear Discussion of precise time and frequency measurement, On Tuesday, 9 August 2022 21:52:45 CEST Avro125 via time-nuts wrote: > I’m wondering if someone would be willing to assist me in getting NTP to > reference time from NIST (Colorado) or NRC (Ottawa) via a dial-up modem. > Either as a primary source, or as a failover in case the GNSS signal is > lost. Sorry, I don't have experience with NTP and dialup-connections, but depending on how trustworthy your mobile phone provider is and what your requirements are, getting the timestamp directly from the GSM network (NITZ) might be an alternative option, even without incurring data charges. (see e.g. https://coders-home.de/en/sync-time-on-linux-via-gsm-1065.html) Cheers, Jürgen -- Jürgen Appel

Hi At least in the US, there are an unfortunately large number of providers / cell sites that are not very diligent about thinks like embedded timestamps….. Since you can get time from a < $10 GPS usb “dongle”, and do so with fairly normal drivers, that would seem to be the quick / easy backup plan. Bob > On Aug 10, 2022, at 5:06 AM, Jürgen Appel via time-nuts <time-nuts@lists.febo.com> wrote: > > Dear Discussion of precise time and frequency measurement, > > On Tuesday, 9 August 2022 21:52:45 CEST Avro125 via time-nuts wrote: > >> I’m wondering if someone would be willing to assist me in getting NTP to >> reference time from NIST (Colorado) or NRC (Ottawa) via a dial-up modem. >> Either as a primary source, or as a failover in case the GNSS signal is >> lost. > > Sorry, I don't have experience with NTP and dialup-connections, but depending > on how trustworthy your mobile phone provider is and what your requirements > are, getting the timestamp directly from the GSM network (NITZ) might be an > alternative option, even without incurring data charges. > > (see e.g. https://coders-home.de/en/sync-time-on-linux-via-gsm-1065.html) > > Cheers, > Jürgen > > > -- > Jürgen Appel > _______________________________________________ > time-nuts mailing list -- time-nuts@lists.febo.com > To unsubscribe send an email to time-nuts-leave@lists.febo.com