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KX-T7436C/KX-T7436C-B
CIRCUIT OPERATIONS
1. KEY INPUT CONTROL CIRCUIT
1) Circuit Operation
Sequential input information (negative 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.
Circuit Diagram
+5V (V1)
D10
D9
D8
D7
D6
D5
D4
D3
D20
IC6
44 RR70
45 RR71
46 RR72
47 RR73
48 RR80
49 RR81
50 RR82
51 RR83
RB0
RD1
RB21
RB11
RB1
R93
R92
R91
63
62
61
60
55
54
53
64
#
R99
R98
R97
R96
R95
R94
R93
R110
CO1
CO2
CO3
CO4
CO5
CO6
SW6
SW5
SW4
SW3
SW2
SW64
SW12
SW11
SW10
SW9
SW8
SW7
FLASH
REDIAL
HOLD
SP
MW
AUTO
MUTE
7
8
9
0
1
2
3
4
5
6
TRANS
PAUSE
PROG
FWD
CONF
INT
CO12
CO11
CO10
CO9
CO8
CO7
SW18
SW17
SW16
SW15
SW14
SW13
CO18
CO17
CO16
CO15
CO14
CO13
SW24
SW23
SW22
SW21
SW20
SW19
SW30
SW29
SW28
SW27
SW26
SW25
SW33
SW34
SW35
SW36
SW37
SW38
SW41
SW42
SW43
SW44
SW45
SW46
SW31
SW32
SW39
SW40
SW47
SW48
SW49
CO24
CO23
CO22
CO21
CO20
CO19
D19
D18
D17
D16
D15
D14
TEL TYPE 1
TEL TYPE 0
D13
RD[0]
RB[21]
RB[11]
RB[1]
R[93]
R[92]
R[91]
RD[1]
RR[83]
RR[82]
RR[81]
RR[80]
RR[73]
RR[72]
RR[71]
RR[70]
Key Input Control Timing Chart
When "RR81" is low status
and the "1" button is pressed,
the key-in information is read.
and the "1" button is pressed,
the key-in information is read.
"1" button is pressed.
"1"
RR70
RR71
RR72
RR81
Key input
R91
(negative
logic)
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