Ah, the hazards of e-mail. Glenn says, "As for the blind leading the blind, AFAIK many people on this list make their living designing/building/ selling precise timing products."
I never meant to say that the blind led the blind. Nor did I comment on anyone's ability to use precision timing instruments. What I did say was that I was blind to the requirements for the unknown telco device logging project. From the way other replies were going, it looked like others were having similar problems. Maybe what got to me was that others were cheerfully offering complex solutions to cover all the bases, when the description of the problem was incomplete. In my 45 years of engineering experience, that always means that the project will cost more than it needs to, and that there is a hazard that it will not work. Five years ago, I worked on time synchronization for an industrial Ethernet project. NTP appeared to be the best choice, so I studied it and corresponded with David Mills. But the devices on the network had limited processing power and memory - limited by available technology and the target cost of the devices. We were able to fall back to SNTP to meet the project requirements. I apologize for trying to apply rigorous methods to this incompletely specified project. As Brooke says, we're here to have fun. Regards, Bill Hawkins -----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Glenn Sent: Wednesday, August 30, 2006 8:15 AM To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] Time syncing question 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 _______________________________________________ time-nuts mailing list [email protected] https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts _______________________________________________ time-nuts mailing list [email protected] https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
