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Applicant: Motorola, INC
TABLE 8 – Microphone Port Specifications
Parameter
Conditions
Input Voltage
No load
Gain
Programmable in 1 dB steps
AC Input
Impedance
R
= 2 KΩ
BIAS
Bias voltage
I
≤ 1 mA
BIAS
Bias Current
2.8.2
Headset Microphone Port
The headset microphone port is designed for use with, but not limited to, a headset audio device. It is
located at pin 57 on the interface connector, named HDST_MIC.
It is designed as a single-ended input and should be referenced to the module analog ground.
The microphone input includes all the necessary circuitry to support a direct connection to a headset
microphone device. It incorporates an internal bias voltage of 1.8V through a 2.2KΩ resistor, and has an
impedance of 1KΩ.
TABLE 9 – Headset Microphone Port Specifications
Parameter
Conditions
Input Voltage
No load
Gain
Programmable in 1 dB steps
AC Input
Impedance
R
= 2 KΩ
BIAS
Bias voltage
I
≤ 1 mA
BIAS
Bias Current
Typ
Min
0
1
1.7
1.8
Typ
Min
0
1
1.7
1.8
Motorola General Business Use
Page 22 of 36
FCC ID: IHDP56JE1
C24 Hardware Interface Manual
Max
Units
1.58
V
PP
31
dB
KΩ
1.9
V
1
mA
Max
Units
1.58
V
PP
31
dB
KΩ
1.9
V
1
mA
Version 0.3
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