Unlike CDMA (where time distribution was an automatic part of the low-level protocol) I suspect the time displayed on many modern phones is not set by the telephony synchronous protocol but rather by IP-over-Wifi packets.
And the packets don't seem to do a very effective job keeping the clock ont he phone correct. My employer gave me a Nokia Lumia 630 "Windows Phone" and its clock has always been off by at least a minute. There was a few years ago, a very nice article about the effort to repair the clocks in clock towers in many cities. What rang most true to me was "if you visit a town they can't even keep the clock correct, who else knows what else is wrong there?". Tim N3QE On Sun, Aug 3, 2014 at 4:37 PM, Brian Garrett <garrettbrian1...@gmail.com> wrote: > Hi all, > > First “time”r here. This may not rank up there with your degree of > time-nuttery, but I haven’t been able to get an answer elsewhere. Recently > I was discussing the issue of how the different cellular providers set > their time, and I told him that I’d read that CDMA phones and towers have > to have their clocks synced to GPS as part of the protocol, whereas GSM > phones do not, and can theoretically be set to wall time, and thus phones > on networks using CDMA would have atomic accuracy all the time since what > they were getting was as good as GPS. > > Well, obviously I was pathetically behind the times. Most everybody these > days including Verizon, which both I and my friend have now, uses LTE , as > you know. I have looked all over for info as to what LTE’s time-setting > requirements are, as implemented by Verizon, but I’ve not seen discussions > of it anywhere. I’ve seen amusing anecdotes over what can happen if your > Android isn’t set to receive the network’s time, or what can happen to your > phone’s clock if you live near a time zone boundary, but no discussion of > how time dissemination is handled in-network. I know my iPhone can be, and > usually is, 2 or 3 seconds fast or slow when checked against an accurate > reference clock, so I’m thinking they can just use wall time like GSM did. > > Has this been discussed on the list before? I haven’t seen anything in > the archives, and no-one at Verizon that we of the unwashed masses have > access to will know the answer Pointers, anyone? > > > Thanks in advance, > Brian > _______________________________________________ > time-nuts mailing list -- time-nuts@febo.com > To unsubscribe, go to > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > _______________________________________________ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.