MANUAL P/N 900000165 REV H
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9
Frequently Asked Questions
The following is a list of commonly asked questions by our customers. If the question that you
wished to be answered is not in the list please contact us. Contact details are found at the end
of this manual under Chapter 11.
Q
Can the NTP80plus act as a stratum 1 server?
A
Yes, Once the NTP80plus has synchronised to a traceable GPS or Off-Air source it will
automatically become a stratum 1 server. In the event of loss of synchronisation this will
be maintained for up to 24 hours at stability in accordance with the internal oscillator
specified.
Q
What packet types will the NTP80plus respond to?
A
ARP requests - to find Ethernet addresses given the TCP/IP address.
ICMP echo requests - to allow ‘pings’ of the NTP server.
UDP connections to port 123 – the defined NTP server port, SNMP V1, V2c
TIME & DAYTIME (port 13 and 37)
FTP for firmware update.
No other packets are accepted.
Q
Can a client have two sources of stratum 1 server so if one server loses the time or is
offline the client can receive time from the second server?
A
Yes, in most cases the client software will allow the configuration for two IP addresses;
one IP address will be the “preferred” server.
Q
How do I know if the NTP80plus is free running? ie the NTP80plus has synchronised to
GPS at some point but has now lost synchronisation?
A
The webpage status and the NTP80plus front panel will indicate that the GPS status is
no longer Normal. The “STATUS” LED on the NTP80plus will be off.
Q
What causes the NTP80plus – GPS Version to loose synchronisation and free run?
A
If the installation of the GPS antenna was originally correct, free running is commonly
caused by the faults such as GPS cable feeder integrity or Water ingress to the antenna
or feeder cable
Summary of Contents for NTP80plus
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