Frequency Reference - Power-Down / Reboot; Timing- Holdover - Microsemi SyncServer S200 User Manual

TIMING Tab
Frequency sources qualified by a hardware TOD source (GPS, IRIG-B) will be stratum-1,
and will continue to serve stratum-1 time even after the original timing reference is dis-
connected.
Frequency sources qualified by an NTP Peer will reflect the same stratum number and Refer-
ence Id / IP Address as the source that qualified them, and will continue to serve time (at that
same stratum) if the Peer is lost.
Frequency sources not qualified by any valid timing source are stratum-16.
Note: If you do not have access to a GPS, IRIG-B or NTP Peer timing reference, then an
alternate – but not recommended -- option is to force-set the TOD through the serial inter-
face. This forces the hardware clock to stratum-1, qualifying any attached frequency ref-
erences also at stratum-1.
Once a frequency source has been locked and is actively steering the hardware clock, that
frequency source can then be used to qualify additional frequency sources.
Example:
1. Lock to GPS;
2. Connect 1PPS to "qualify" it.
3. Disconnect GPS; 1PPS remains qualified and steers the clock.
4. Connect 10MHz; the 10Mhz reference is now also qualified with the same stratum and
Reference Id as the 1PPS.

Frequency Reference - Power-Down / Reboot

Power Down
Upon power down, the frequency source essentially becomes "unqualified" due to the real
time clock's (RTC) "time away" (no matter how long) from monitoring that frequency input.
The SyncServer now comes back up as stratum-16 and will stay there until it is re-qualified
with a valid time source.
Reboot
When the system starts up, it is forced to stratum-16. It can only ever claim stratum-1 once it
has been connected and locked to a valid TOD reference (GPS, IRIG-B, NTP Peer). Once
this happens, any connected frequency reference is then "qualified" to serve stratum-1 time.
See Steering with a Frequency Reference (on page 44).

TIMING- Holdover

Overview
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