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5 ANZ14 (NET Option)
5 ANZ14 (NET Option)
5.1 Network Time Protocol (NTP)
NTP is a common method for synchronization of hardware clocks in local und global networks. The basic
concept, version 1 [Mills88], was published in 1988 as RFC (Request For Comments). Experiances made from
the practical use in Internet was followed by version 2 [Mills89]. The software package NTP is an implemen-
tation of the actual version 3 [Mills90], based on the specification RFC-1305 from1990 (directory doc/NOTES).
Permission to use, copy, modify and distribute this software for any purpose and without fee is hereby granted
(read File COPYRIGHT).
NTPs way of operation is basically different from that of most other protocols. NTP does not synchronize
all connected clocks, it forms a hierarchy of timeservers and clients. A level in this hierarchy is called a stratum,
and stratum-1 is the highest level. Timeservers of this level synchronizes themselves by a reference time source,
such as a radio controlled clock, GPS-receiver or modem time distribution. Stratum-1-Servers distribute their
time to several clients in the network which are called stratum-2.
A high precision syncronization is feasible because of the several time references. Every computer syncronizies
itself by up to three valued time sources. NTP enables the comparison of the hardware times and the adjustment
of the own clock. A time precision of 128 ms, often better than 50 ms, is possible.
5.2 Time and Date Display with NTP synchronized Reference
ANZ14/NET is a LED display with network (Ethernet) connection. It was designed to display the time (hours,
minutes and seconds) as well as the date (day, month, year and day of the week). The free running clock
is beeing synchronized cyclic via the network connection (RJ45 10/100MBit) by a NTP time server using the
Network Time Protocol.
The UTC time sent by the NTP server is converted into the users local time by configurable parameters and
displayed correspondingly. A dot in the LED display and/ or a numerical error code indicates a malfunction.
Configuration occurs via network using a Telnet connection.
After the network connection has been established successfully and the ANZ14/NET gets its time over the
network the display is synchronized to the time of the available NTP server and to the configured time zone.
This is recognizable by the extinguishing of the decimal-point for seconds (depending on the query-interval ->
NTP time request).
ANZ14/ANZ14DCF/ANZ14NET Date: 28th October 2019 17