PTB News 1/2001 (301 kB) PTB News 1/2001, English edition, Issue March 2001
Time signals from the atomic clocks of the PTB are synchronizing an increasing number of computer systems around the world via the internet: Over 2,5 million times per day external computers of scientific institutions and industrial companies, of small-scale enterprises and private persons access the two public time servers of the PTB. The jitter of the time signals delivered is typically only 20 µs.
In information technology (e. g. for process control, dating of measurement data or recording of events), it is frequently necessary to synchronize server systems with each other and to link up their operating system time with the Universal Time Coordinated (UTC). The Network Time Protocol (NTP) is a standard protocol established on the internet. It is the obvious protocol for this purpose and suitable for setting up a hierarchic system of time servers. PTB operates two servers for this purpose under the internet addresses ptbtime1.ptb.de and ptbtime2.ptb.de. For practical use of the NTP time information a software package is needed to support the NTP protocol. Suitable software is available for all common operating systems. This service supplements the previous time transmission service by means of DCF77 radio clocks or GPS receivers.