[time-nuts] Time syncing question

[Glenn]

Telco's know exactly what time it is. Although, frequency is much  
more important than time.  Central Offices use either Rb or Cs for a  
Time & Freq. standard. They need to keep all the trunk signals in  
perfect sync to keep from loosing bits.

Cell sites generally use GPSDO's. Either OXCO or Rb. Most of the Rb  
sources on ebay are from cell site upgrades. Ditto for the Motorola  
Oncores.

_Most_ cell phones set their time to "network time." Usually within  
one second. Although I have seen cell phones set themselves and be  
off by nearly a minute.

If leap seconds are a problem, use TAI, not UTC.

As for who pays, I've found that (in general), if something isn't  
going to increase profit, or decrease expenses, it's probably not  
going to get funded by a business. Hence, many of us just do this for  
the fun of it.

As for the blind leading the blind, AFAIK many people on this list  
make their living designing/building/selling precise timing products.  
Others have experience using precise timing equipment.

cheers,
glenn