DS_1x66B_001
73M1866B/73M1966B Data Sheet
3.4.2 Call Progress Monitor
The Call Progress Monitor monitors activities on the line. The audio output contains both transmit and
receive data with a configurable level individually set by Register 10h.
Figure 10 shows the frequency response of the Call Progress Monitor Filter based upon the
characteristics of the device plus the external circuitry as shown.
Figure 10: Frequency Response of the Call Progress Monitor Filter
C1 0.1uF R1 120K
R2
120K
LS1
AOUT
VCC
AT-2308
INTERVOX
R3 120K
4
1
5
8
-VIN VOUT1
CD
VOUT2
VCC
2
3
6
7
VREF1
VREF2 GND
V+
C3
+
C2
2.2uF
C4
1uF
U1
NJM2135
1uF
Figure 11: Demo Board Circuit Connecting AOUT to a Speaker
Table 14: Component Values for the Speaker Driver
Quantity Reference
Part Description
Ceramic capacitor
Part
1
1
2
1
3
1
C1
0.1 μF
C2
C3, C4
LS1
Ceramic capacitor
Ceramic capacitor
Sound transducer
1/8 W resistor 0603
Audio amplifier
2.2 μF (optional)
1 μF
Speaker (Intervox)
120 kΩ
R1, R2, R3
U1
NJM2135 (New Japan Radio)
All measurements are at the AOUT pin with CMVSEL=0. Note that when CMVSEL=1, the peak signal at
AOUT is increased to approximately 1.11 Vpk.
Rev. 1.6
21
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