Sony DNW-7/7P Operation Manual page 247

6
Set the F-RUN/SET/R-RUN switch to F-RUN, and check that the
counter indication changes regardless of whether the tape is running.
7
By setting the DISPLAY switch to DATA, and set the DATA
DISPLAY switch to U-BIT, you can check that the user bit value set
is displayed.
Chapter 6 Maintenance
6
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