EXFO OTDR 2 - Manual (Page 74)

Testing Fibers
66 OTDR
Monitoring Fibers in Real-Time Mode
To deactivate the real-time mode:

If you have the full OTDR application, when you want to stop
monitoring, tap Stop RT.
OR
If you only have access to the OTDR in Real Time mode, tap Stop Real
Time.

If you have the full OTDR application, you can also stop the real-time
acquisition by starting an averaged acquisition. All the wavelengths for
which boxes are selected will be tested in averaging time interval
mode (not only the highlighted one).