HP 4934A Operating And Calibration Manual page 14

18 START RESET sets the Impulse Noise counter to zero and starts the Impulse
Noise measurement.
19 FILTER selects one of the filters in the noise measurement modes.
C-MSG
3 kHz FLAT
15 kHz FLAT
PRGM
SOkBIT
20
MONITOR VOLUME controls the volume of the monitor speaker.
21
In the LEVEL FREQ mode, the blue keys FI to F4 select preset frequencies. At
switch-on these frequencies are:
FI: 404 Hz
F2: 1004 Hz
F3; 2804 Hz
F4: 2713 Hz
New frequencies can be assigned to FI to F4, see Page 2-9.
1-4 Getting Started