Its; Monitor Section - Panasonic KX-MB771GR Service Manual

KX-MB771GR
6.5.
ITS (Integrated telephone System) and MONITOR SECTION
6.5.1. GENERAL
The general ITS operation is performed by IC200 which has a handset circuit. The alarm tone, the key tone, and the beep are
output from Soc IC300.
6.5.1.1. TELEPHONE MONITOR
1. Function
This is the function when you are not holding the handset and can hear the caller's voice from the line.
2. Circuit Operation
(Telephone Monitor Signal Path)
Signals received from the telephone line are output through at the speaker via the following path.
3. Signal Path
TEL LINE→D103→Q104→C106→IC101(3-5,6)→IC100(9,10-5)→IC300(AD26-AB24)→IC200(4-1)→IC202(2-1)→IC204(4-
5,8)→CN200(1,2)→CN58(1,2)→CN57(1,2)→SPEAKER
6.5.1.2. MONITOR CIRCUIT
1. Function
This circuit monitors various tones, such as (1) DTMF tone, (2) Alarm/Beep/Key tone/Bell.
2. Signal Path
a. DTMF MONITOR
(Speaker Operation)
IC300(AB24)→IC200(4-1)→IC202(2-1)→IC204(4-5,8)→CN200(1,2)→CN58(1,2)→CN57(1,2)→SPEAKER
(Handset Operation)
IC300(AB24)→IC200(4-16)→IC203(4-8)→CN200(7,8)→CN58(7,8)→OPTION HANDSET UNIT
b. ALARM/BEEP/KEY TONE/BELL
IC300(B20)→IC202(2-1)→IC204(4-5,8)→CN200(1,2)→CN58(1,2)→CN57(1,2)→SPEAKER
6.5.1.3. TAM INTERFACE SECTION
1. Function
When TAM is connected to this unit, the unit receives documents for FAX calls or the external TAM records a voice message
automatically.
2. Circuit Operation
The TAM INTERFACE circuit consists of Soc(IC300) to detect the other party CNG signal, and RLY100 to separate EXT.TAM.
a. CNG signal detection circuit
The CNG signal from the other party's FAX is detected in Soc IC300
(Signal path)
TEL LINE→IC101 (8,9 - 5,6)→IC100 (9,10 - 5)→IC300(AD26)
b. Remote receiving
This is the parallel-connected DTMF signal for the TEL or EXT.TEL mode between T and R. When the other party is a
FAX, the unit switches to FAX receiving.
(Signal Path)
TEL LINE→IC101 (8,9 - 5,6)→IC100 (9,10 - 5)→IC300(AD26)
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