Microphones

Introduction

Use the Confidea-D MIC30SL (30 cm) - D MIC40SL (40 cm) - D MIC50SL (50 cm) removable microphones with the different delegate and chairman units. This microphone ha a unidirectional response for optimum performance even in noisy conditions, and has a very low susceptibility to RF-interference from mobile phones.

Electrical and acoustic properties

Parameter	Value
Transducer type	Back electret (condenser)
Operating principle	Pressure gradient
Polar pattern	Uni-directional, cardioïd
Nominal impedance	Bias resistor = 1k2 Vdd = 3.3 V DC, SPL = 1Pa
Max.SPL at 1 kHz	110 DB SPL (1% THD+N)
Signal to noise ratio	>67 dB(A)
Free field sensitivity	9.4 mV/Pa, ±3 dB @ 1 kHz or (-40.5 dB, 0 dB = 1 V/Pa @ 1 kHz)
Power supply	3.3 V DC, 0.5 mA
Consumption	0.5 mA (without LED ring); max. 25 mA (with illuminated ring)

Microphone connector

Figure 1-10 Microphone connections

pin 1 : microphone GND
pin 2 : microphone signal
pin 3 : unused
pin 4 : LED +
pin 5 : LED –

Operation

The microphone contains the following elements.

Indicator ring: shows the status of the microphone
Union nut: attaches the removable microphone to the unit
Microphone plug: connects the microphone to the unit

The color of the microphone indicator ring shows the status of the microphone.

Color	Condition
Red (on)	Microphone active
Red (blinking)	Last minute of speech time (if set via software) or Speech request (if set via software)
Green (on)	Microphone is initialized
Green (blinking)	Microphone request