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SM010-3 Siemens SD 270 Operating & Service Manual Page 13
INVERSE
Presents the signal continuously; the indicator above the
key illuminates green. Pressing the PRESENT key
interrupts the signal presented.
+20dB
This enables tone levels to be presented with up to 20dB
higher output; press the key and then use the SIGNAL
rotary control to access the extra 20dB; a green indicator
above the key is used to show that the function is active,
and an additional display message indicates levels greater
than 100dBHL.
Note: this function will not operate if
continuous tone presentation has been enabled.
LOCK
Synchronous masking function. Locks signal and mask
output at a constant difference when the SIGNAL control is
adjusted. An indicator above the key illuminates green
when active. The MASK
control adjusts masking
independently.
AIR
Outputs the signal to the earphones; the indicator above
the key illuminates green
BONE
Outputs the signal to the bone vibrator; the indicator above
the key illuminates green
FREEFIELD
Routes signals to LINE output socket; the indicator above
the key illuminates green
Hz
Press the
key to lower the frequency and the
key to
increase the frequency.
PRESENT
Press to present the displayed test signal to the test
subject. The “Present” indicator to the left of the display will
be illuminated green during tone presentation.
TALKOVER
Interrupts the test and routes operator’s voice from the
internal microphone (or MIC 1 input) to the headset. The
attenuation level can be adjusted with the SIGNAL rotary
control.
TALKBACK
While selected (as indicated by the indicator above the
key) the signal from MIC2 is routed continuously to the
MONITOR output. Press the key again to de-select. The