Panasonic KX-T7453, Service Manual, Page: 13 / 57

AG3 50
--- Power
supply, etc. Ground terminal of analog circuit.
A5V4 51 5V power terminal of analog circuit.
AP2HO 52
Analog
output
Analog Output terminal of microphone amplofier H2.
Connect the capacitor of 0.1 F to this terminal to cut the DC
AP2HI 53
Analog
input Inverting input terminal of microphone amplofier H2.
Connect the capacitor of 0.1 F to this terminal to cut the DC
AP1HO 54
Analog
output Output terminal of microphone amplofier H1.
Connect the capacitor of 0.1 F to this terminal to cut the DC
AP1HN 55
Analog
input Inverting input terminal of microphone amplofier H1.
Connect to the handset.
AP1HP 56
Analog
input
Analog
Non-inverting input terminal of microphone amplofier H1.
VREFM 57
--- Power
supply, etc. Reference voltage terminal of microphone amplifier.
Connect the capacitor of 40 F between this terminal and pi
56 (MICG).
AG4 58 Ground terminal of analog circuit.
APMO 59
Analog
input
Analog Output terminal of microphone amplifier.
Connect the capacitor of 0.1 F to this terminal to cut the DC
APMN 60
Analog
input Non-inverting input terminal of microphone amplofier M.
6. BLOCK DIAGRAM
7. CIRCUIT OPERATIONS
7.1. KEY INPUT CONTROL CIRCUIT
1) Circuit Operation
Sequential input information (negativa logic) from the DSHS proprietary telephone is executed by
dynamic scanning.
The ports RR70 to RR73, RR80 to RR83 of IC6 are brought to low status consecutively.
If a key is pressed, the key-in information input is executed by ports R91 to R93, RB1, RB11, RB21,
RB0, RD1.
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