NTP server

[Andy Frodsham]

In the old Windows 95 days I had a small radio-controlled clock unit (about the size of a bedside digital alarm clock) with a serial cable that connected to my PC and kept the clock perfectly synced. Such units are available commercially in the UK.

Could something like this be used to sync the projection server?

I've also heard of people making-up Rasberry Pi modules to perform such a task.

[Harold Hallikainen]

In the US, the radio controlled clocks receive WWVB on 60 kHz ( https://www.nist.gov/pml/time-and-fr...o-station-wwvb ). I think a concern with using NTP, GPS, or radio time standards for a secure clock is the possibility of spoofing the source. The DCI 6 minute limit seems like a good security measure. You can use whatever you want to make the adjustment (manual, NTP, or whatever) as long as it stays in the limit. The previously mentioned Maxim clock chip looks nice, though, as previously mentioned, I'd prefer a 64 bit counter to YYYYMMDDHHMMSS scattered among registers. Maxim picked up these products from Dallas Semiconductor. Back in the 1980s, I designed a product using the Mostek MK48T02 TimeKeeper RAM. It was a 2 kB static RAM with RTC and built in crystal and battery. I still have a couple of those products around. Have to see if the batteries are still good. One clever thing I remember about those chips is that the oscillator current was too low to start the oscillator. There was a register bit to "kick start" the oscillator.

[Marcel Birgelen]

How difficult can it be to implement an "unspoofable" signed time sync using a generic REST API or something similar, with a signed request and a signed answer? This could allow any clock that drifted way too much to be resynced securely. Milisecond accuracy isn't really relevant anyway for this application.

[Torsten Juergens]

Our IMS3000 and CP4415 do not accept the local windows ntp server in the office since the beginning of time.

Now I have installed an ntp server from Meinberg and the CP4415 is now synchronizing.

https://www.meinbergglobal.com/english/sw/ntp.htm

Installation instructions are available here.

http://www.satsignal.eu/ntp/setup.html

But the IMS3000 still doesn't really want to.

At the weekend I will try a direct connection via my laptop with the Meinberg ntp server.

Let's see what happens.

[Steve Guttag]

I have synced IMS3000s to Windows NTP pretty much everywhere...same with Christie projectors. It is often overlooked to open up the windows firewall for UDP port 123 (incoming) to allow it. One also has to properly configure their NTP, which involves modifying the registry.

http://www.film-tech.com/vbb/forum/m...4471#post24471

[Torsten Juergens]

Steve, I used your instructions including the trigger info.
Leo's check.
First with firewall rule UDP 123 on. Then with Firewall off.
No success

[Steve Guttag]

Have you confirmed that your Windows computer is getting good NTP? Some networks will block UDP123 (an IT strategy is to block all ports until it is requested that a port be open). Seriously, I think most, if not all of my IMS3000s sync off of a Windows computer (Win 7, Win 10 or one of the many Windows Server variations). There is some key bit of information that is missing here.

BTW...is the Secure clock beyond its shift range? Does it say something like 330/360 and it needs more than 30-seconds of shift?

[Torsten Juergens]

Here is the missing information.

Yes Steve, you are right. The server shows 313/360.
Last synchronization date: Wednesday, 17 Aug 2022 19:32:58
Last synchronization offset: 4 seconds

[Steve Guttag]

You need to report this to Dolby. I think IMS3000s have a bit of a secure clock issue and they drift (probably when off) like the CAT745 did...but to a lesser degree.

[Jon Dent]

I mentioned much earlier in this thread that our IMS3000 servers had some pretty bad drift too. Since getting a proper NTP it seems to have gotten better, but the offset budget still creeps up every few days.

Dolby was pretty helpful when I contacted them and they sent over the offset extension package that's been mentioned here pretty freely.

[Pedro Augusto]

Good afternoon.
I wanted to add an NTP connection to Christie series 2 projectors, but I can't.

Where I have to activate it is in Administrator Setup > Time Setup, right?

I still can't activate this option, am I doing something wrong?
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