[time-nuts] Time syncing question

[Joseph Gray]

For various reasons, I can't change the software on the device. It would be 
even more impossible to modify the hardware. The device's time is settable 
at any time via either serial port or HTTP, as I mentioned earlier. 
Considering what I am allowed to do with the device, I think an external 
program to adjust the time is the best solution.

----- Original Message ----- 
From: "Didier Juges" <didier at cox.net>
To: "Discussion of precise time and frequency measurement" 
<time-nuts at febo.com>
Sent: Monday, August 28, 2006 7:02 PM
Subject: Re: [time-nuts] Time syncing question


>I guess it would help to know if the phone system computer runs over a
> general purpose OS, such as Linux or a variation of Windows or other
> GPOS. If so, you may be able to install a good time keeping utility
> designed for that OS and have it steer and update the RTC from an NTP
> time server. If not (not running a GPOS), you are probably out of luck,
> unless the OS allows some sort of scripting that would let you update
> the time periodically.
>
> You did not say if there was any facility at all to update the RTC other
> than when the system boots. If not, there again you are out of luck.
>
> It may be possible (and simpler, while not a 100% fix) to change the
> RTC, or adjust it's crystal for better time keeping.  That would be,
> horror, a 100% hardware solution, but sometimes a hardware fix is more
> effective... Maxim has a couple of chips specially designed with very
> stable 32,368 Hz oscillators and built-in xtal. Check their web site for
> "Extremely accurate RTC" (DS3232 and DS3234). These chips are intended
> to be used with a uC via a serial bus (in which case they provide full
> calendar and other functionality), but you can simply use the 32 kHz
> output to drive your existing RTC and take advantage of the temperature
> compensated TCXO. Now, if you mate the chip with a uC, you could even
> adjust the oscillator for best initial accuracy.
>
> Didier KO4BB