CC864-DUAL Hardware User Guide
1vv0300791 Rev 4.4 – 2011-01-26
Reproduction forbidden without Telit Communications S.p.A’s. written authorization - All Rights Reserved.
Page 45 of 63
MIC_MT-
1.8V
1u
F
Earpiece
32
Ω
100pF
100pF
100pF
MIC1
27pF
27pF
2.2K
Ω
2.2K
Ω
EAR_MT-
CC864-Dual
Module
Pin 15
Pin 16
Pin 12
Pin 11
3.9.5. Headset
Interface
This configuration uses a standard mono single-ended microphone interface.
The positive input contains the signal and is AC-coupled directly to the microphone,
while the negative input is AC-coupled to ground. A 100pF capacitor is connected
across the two AC-coupling capacitors on the microphone side.
A 27pF capacitor bypasses the microphone output.
The positive microphone terminal is connected to the bias voltage (1.8V) through a
2.2 Ohm bias resistor. The 1.8V output provides up to 1 mA bias current for the
microphone.
The bias power is bypassed by a 0.1uF capacitor.
The figure below shows the basic “headset”-configuration: