Its (Integrated Telephone System) And Monitor Section; Atas (Automatic Telephone Answering System) Section - Panasonic KX-FG2452CX Service Manual

KX-FG2452CX
6.9.

ITS (Integrated Telephone System) and Monitor Section

6.9.1. General
During the monitor operation, the speaker output passes through the power amplifier (IC705) [Digital board].
The DTMF signal is output from the modem (IC701: digital board). The alarm tone, the key tone, bell tone, and beep are output from
gate array IC501 (digital board). During a pulse dial operation, the monitor tone is output from gate array IC501.
6.9.2. Speakerphone Circuit
1. Function
The circuit controls the automatic switching of the transmitted and received signals, to and from the telephone line, when the
unit is used in the hands-free mode.
2. Circuit Operation
The speakerphone can only provide duplex.
3. Signal path
Refer to Check Sheet for Signal Route (P.148).
6.9.3. Handset Circuit
1. Function
This circuit controls the conversation over the handset, i.e. the transmitted and received voices to and from the handset.
2. Signal path (Transmission signal)
Refer to Check Sheet for Signal Route (P.148).
3. Signal path (Reception signal)
Refer to Check Sheet for Signal Route (P.148).
6.9.4. Monitor Circuit
1. Function
This circuit monitors various tones, such as 1 DTMF tone,2 Alarm/Beep/Key tone/Bell 3 Dummy ring back tone.
2. Signal path
a. DTMF MONITOR
(Speaker Operation)
Refer to Check Sheet for Signal Route (P.148).
(Handset Operation)
Refer to Check Sheet for Signal Route (P.148).
b. ALARM/BEEP/KEY TONE/BELL
Refer to Check Sheet for Signal Route (P.148).
c. DUMMY RING BACK TONE
Refer to Check Sheet for Signal Route (P.148).

6.10. ATAS (Automatic Telephone Answering System) Section

1. Function
The ATAS main operation is performed by the special IC701 (MODEM). IC504 (FLASH MEMORY) control signals are input
from ASIC IC501.
a. Greeting/Message Recording
b. ICM Recording
c. Greeting/Message/ICM play to speaker
d. Greeting/Message/ICM play to Tel Line
e. Vox Detection
2. Signal Path
Refer to Check Sheet for Signal Route (P.148).
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