Datasheet

DS_1x66B_001 73M1866B/73M1966B Data Sheet
Rev. 1.6 21
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
U1 NJM2135
CD
1
-VIN
4
V+
6
GND
7
VOUT1
5
VOUT2
8
VREF1
2
VREF2
3
AOUT
VCC
VCC
R3 120K
+
C2
2.2uF
LS1
INTERVOX
AT-2308
C4
1uF
R2 120KR1 120K
C3
1uF
C1 0.1uF
Figure 11: Demo Board Circuit Connecting AOUT to a Speaker
Table 14: Component Values for the Speaker Driver
Quantity
Reference
Part Description
Part
1 C1 Ceramic capacitor 0.1 μF
1 C2 Ceramic capacitor 2.2 μF (optional)
2 C3, C4 Ceramic capacitor 1 μF
1 LS1 Sound transducer Speaker (Intervox)
3 R1, R2, R3 1/8 W resistor 0603 120 kΩ
1 U1 Audio amplifier 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.