MOUNTING AND INSTRUCTION MANUAL DTS 4148S.grandmaster

8.4 Time acceptance from external AFNOR-A/C, IRIG-B12x source

The stratum value is calculated same as with DCF/GPS synchronization (chapter 8.3).

As IRIG-B120 to 123 time codes do not provide information about the current year, the

DTS 4148 has to be synchronized first from another time source or the date has to be set manually. The DCF input and the IRIG input cannot be used at the same time for the synchronization (redundant time source with DCF and IRIG synchronization is not possible).

AFNOR and IRIG-B126 contains the time and date information.

Attention:

After more than 5 days without power, the DTS 4148 loses the date information. When synchronized with IRIG-B120 to 123 it has to be set again manually.

8.5 Time acceptance from NTP

Acceptance:

 As NTP RFC 1305, RFC 5905 (www.ntp.org)

(see http://ntp.isc.org/bin/view/Servers/WebHome for internet-server)

Stratum in normal, synchronized operation:

 Stratum value of DTS is always one step higher than that of the current NTP time server

Stratum in case of an error

 As NTP RFC 1305, RFC 5905 (www.ntp.org)

8.6 NTP as backup

If DTS 4148 is synchronized with a DCF or GPS source, the NTP can be used as redundancy source. This function is active, as soon as at least one grandmaster is configured in menu ‘2. Configuration’  ‘2. Time handling  ‘4. NTP server’).

Stratum in normal, synchronized operation:

 Equal Stratum value “Time Acceptance from an external source (DCF or GPS)”

Behavior in case of an error:

 Failure of primary Source:

"St. est": Means: Expected NTP Stratum of the NTP sources

"St. est" = MAX(Stratum NTP candidates)

 Means: "St. est" contains the stratum value of the poorest NTP source.

If internal Stratum > "St. est" + 1, then change to NTP as source takes place

(internal stratum is one step higher than that of the poorest available NTP source).

 As soon as the primary source is available again, the changes are set back.

© MOBATIME

 NTP v4 (compatible with v3) as per RFC 1305, RFC 5905 (port 123)

 SNTP (UDP), RFC 2030 (port 123)

 PTP (UDP), IEEE 1588-2008 (V2) (ports 319 and 320)

 TIME (TCP/UDP), RFC 868 (port 37)

 DAYTIME (TCP/UDP), RFC 867 (port 13)

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