Model 9289
Spectracom Corporation
NetClock/NTP Network Time Provider Instruction Manual
7-16
call after the call is finished it is possible to start a call as a certain call type and actually use it
as another call type. Here is a description of each of the four possible call types.
7.1.7.1 Calibration
Call
Calibration calls are done to characterize the call latency. A user specified number of calls will
be made over the calibration period and the average latency will be used to adjust all future
calls. The calibration will only be done at the user’s request and may be started only while in
sync from another time source. Calibration calls may be continued into holdover, but will be cut
off if the unit goes out of sync at any point during the calibration period.
7.1.7.2
Time Verification Call
Time verification calls are made to verify the unit still has acceptable time and to correct for any
leap seconds that may be asserted while the reference is not available. Calls will be made on a
user specified time table. If the call interval is more than a month leap seconds may be missed.
If a leap second is to be inserted at the end of the month then the clock will be scheduled to do
so. If the time is off by more than half a second then the unit will be immediately put into
unsynchronized mode (time synchronization lamp will extinguish and time outputs will be
ignored).
7.1.7.3
Time Sync Call
Time synchronization calls occur to set the second and sub second timers and to check for any
leap seconds. If a call is successful the timer will be set and the unit will be put in holdover
mode with the holdover timer reset. In addition if a leap second is to be inserted at the end of
the month then the clock will be scheduled to do so. Time synchronization calls will be made
once the unit has gone into unsynchronized mode until it obtains sync from another time source.
During this period, calls will be made on a user specified timetable or any time the unit goes out
of sync.
7.1.7.4
Modem Test Call
Test calls are calls that make sure the modem is working. The modem will call out and check
for valid time messages. The unit will log “test passed” if it was able to get good time messages
or failed if it was not. No changes will be made to the system time. Testing can be done only in
sync from another time source and can either be on a specified interval or as requested.
7.1.8 Verify
Modem
Operation
For the modem to function with the NetClock, the client mode must be selected in the System
Modem Configuration screen for the NetClock to accept the change from console mode.
If the unit is already powered-up and not synchronized, choosing dial-out now and hitting submit
will cause the unit to connect to NIST. If the unit is already synchronized, this option is not
available (The dialout now function is not available for operation if the NetClock is in either
holdover or sync mode). To operate the modem if it is in currently in sync, disconnect the
antenna and wait until the variable holdover period expires or power cycle the unit to clear the
sync condition. Then, the dial-out now function will be available.
Once the NetClock has dialed and synchronized to NIST, the unit will be in holdover mode until
the variable holdover period expires (Devices syncing to the NetClock will still sync) indicated by
the sync light flashing green. After the variable holdover expires, the unit will declare loss of
Summary of Contents for 9289
Page 18: ...Model 9289 Spectracom Corporation NetClock NTP Network Time Provider Instruction Manual 1 8...
Page 36: ...Model 9289 Spectracom Corporation NetClock NTP Network Time Provider Instruction Manual 2 18...
Page 154: ...Model 9289 Spectracom Corporation NetClock NTP Network Time Provider Instruction Manual 3 118...
