EXFO FTB/IQS-85100G Packet Blazer for FTB-500/IQS-600 - Manual (Page 318)

Test Functions
308 FTB/IQS-85100G
RTD
Measure Delay Button
Allows enabling the round trip delay measurement.
For Single mode, the test is performed once and stops (the Measure Delay
button turns off by itself). The Measure Delay button is only available when
the test is running.
For Continuous mode, the test is performed continuously until the RTD
test or the test case itself is stopped. However, the measurement will only
start if the test is running or when it will be started. The Measure Delay
button turns off by itself when the auto-calibration fails.
Note: The Round Trip Delay (RTD) auto-calibration generates some bit errors
when turning on the RTD measurement while the test is running or when
starting the test while the Measure Delay button is enabled. A far end
testing equipment will detect those bit errors.
Status
Indicates the test status of the RTD test. The status is only available when
the test case is running.

Ready indicates that the last calibration sequence has been successful
and the test is now ready to perform RTD measurement.

Running indicates that the RTD test is running.

Cancelled indicates that the RTD test has been stopped before its
completion.

Calibration Failed indicates that the test calibration failed due to at
least one of the following conditions:

Internal errors.

Presence of high number of bit errors.
Therefore the RTD statistics becomes unavailable since the test does
not allow RTD testing.