MEDISWITCH
®
Rehab and Care Technology
Instruction Manual
VarioFon
noise detecting unit
Nurse call and personal transmitter technologies
rehab and care technologies
Phone.: +49 2208 9492 0
Fax.: +49 2208 9492 32
Lehmann Electronic GmbH Niederkassel
Copyright © 2019
LE324 V1.14 Page 2 von 4
Warning
The noise detecting unit enables persons to trigger calls despite significant motoric restrictions. The detection of noises
as calls is limited by physical laws. Therefore, call triggering cannot be guaranteed. This must be taken into consideration
when using the device.
Setting the Noise Detecting Unit
Note: The positions of the controls and indicators can be seen in Fig. 1.
Adjusting the Microphone Sensitivity
Adjust the amplification using the microphone sensitivity control such that the call is securely triggered when the calling person generates
the noise intended as a call.
Important: A high sensitivity results in a reliable generation of a message, however, it also
increases
the possibility of false calls
.
However, it is safer to allow false calls than to set the sensitivity too low.
Table 1: Controls and Indicators
Indicator/control element
Illustration Operating state / function
Call button
(P1)
(red)
Enables triggering of a call independently of the call microphone.
Call indicator LED
(orange)
(above the call button)
Lights up as long as a call is active.
Microphone
ON/OFF
button (P2)
The microphone status LED displays the current status.
LED microphone status
Lights up when the microphone is switched off.
Flashes for approx. 10 seconds when the microphone is switched ON.
The LED indicator is off when the microphone is switched on.
Microphone sensitivity control
Turn clockwise to increase the amplification and thus the sensitivity.
Noise filter control
See the following chapter “Adjusting the noise filter”.
Adjusting the noise filter
(from left to right, corresponds to from top to bottom in table 2)
The noise filter allows for digitally filtering out background noise for reducing false alarms.
Four general filter levels with slight plus/minus offsets according to table
2
can be set with the seven-stage scale.
Rotate the noise filter rotary knob. The respective filter level is indicated by the call indicator (orange) and microphone status (green)
LEDs according to table
2
. When the rotation stops, these LEDs revert to the normal indicator mode after approx. 1 second and indicate
the current microphone status (ON or OFF according to table
1
).
Table 2: Noise Filter Settings
LED
Function
(note: the description of operation serves only as a guideline for presetting. The optimum setting must be
determined by trial and error.)
Low response characteristics:
Low risk of false alarms
Loud background noise such as talking, music from radio or TV is filtered out. Short and louder noises such as the loudly
enunciated word “hello” or “help”, for example, result in call triggering.
Medium response characteristics:
Medium risk of false alarms
Constant background noise is filtered out. Noises exceeding the background noise and being of medium length, such
as enunciation of the word “nurse”, for example, results in call triggering.
High response characteristics:
High risk of false alarms
Nearly every noise differing from relatively low-level noise and constant background noise results in call triggering. High
risk of false alarms.
Maximum evaluation:
Very high risk of false alarms
Background noise is filtered out only to a very small extent and may result in call triggering.
Green
Orange Green
Red
Orange
