Call Progress and "Voice" Detector
CMX683
CONDITIONS
No Signal
Call Progress Signal:
Will detect 350+440, 400+450, 440+480, 400,
425, 440, 450, 480+620, 600 and 620Hz tones
DTMF Signal
Non Call Progress Signal (eg voice)
FAX/Modem or other out-of-band signals
CP DETECT
0
1
"VOICE"
FAST/SLOW
0
0
0
0
0
0
1
0
Table 1 Decode Output Truth Table
6.
Application Notes
On power-up, it will take no more than 15ms to initialise the internal state. This delay should be
accounted for before the CP DETECT, VOICE SLOW and VOICE FAST outputs are valid.
Figure 3 A typical Telephone Line Circuit Application
R1 470kΩ
R2 470kΩ
R3 470kΩ
R4 470kΩ
R5 100kΩ
R6 100kΩ
C2
C3
C4
C5
0.1µF
0.01µF 250V
0.01µF 250V
0.1µF
Note:
1. Resistors
±1%,
Capacitors
±20%,
unless otherwise stated.
2. A low offset opamp is needed. The decoupling capacitor C1 is not required if the quiescent
dc
level at the opamp output is the same as VREF.
©
2002 CML Microsystems Plc
8
D/683/1
CMLMICRO [ CML MICROCIRCUITS ]
