0.6V :
OFF HOOK
SP-PHONE
SPEAKER AMP
HAND SET
JA
C
K
SP ON :
L
SP OFF :
L
2.5V
HOOK SWITCH
RESET CIRCUIT
4.5V :
ON HOOK
SP V
OLUME
OPERA
TION
H OR L
JOG SWITCH
SP-PHONE RECEPTION
LED
0.63V
PBX
12V
REGULA
T
OR SECTION
DPITS
GA
TE ARRA
Y
XDP J
A
CK
SP-PHONE TRANSMISSION
HANDSET RECEPTION
HANDSET TRANSMISSION
OHCA TRANSMISSION
OHCA RECEPTION
COMMUNICA
TION
RESET :
H 5V
NORMAL :
L 0V
MU
A
: H
: L
CODEC
R1
4.7K
R2
4.7K
R6
4.7K
R3
4.7K
C4
68P
C6
68P
C7
100P
C5
100P
Q1
Q2
R4
33
Ω
R7
33
Ω
C3
50V1
µ
C80
50V1
µ
+5V(V1)
R8
4.7K
R11
4.7K
R9
4.7K
R12
4.7K
C8
47P
C9
47P
R10
4.7K
R13
4.7K
VREF
T1
4
59
10
1
26
7
R5
470
D1
L1
L2
R16 47
C15
6.3V1000
µ
R18 47
R20 47
R22 47
R24 220
R25 47
R19 220
R21 220
R17 220
R23 220
R26
10
Ω
C16
6.3V1000
µ
D11
R41
4.7K
R46
3.9K
R44
18K
R45
10K
Q25
IC5
PO-
4
PDI
10
DT
13
DR
8
PO+
5
P1
3
RO
-
2
VA
G
20
BCLKT
12
BCLKR
9
MCLK
11
TG
17
VSS
15
TI+
19
TI
18
VDD
6
FST
14
FSR
7
MU/A
16
RO
+
1
C64
0.1
R47
68K
R48
68K
R49
56K
R50
120K
R51
120K
C69
0.1
AG
C68
16V330
µ
R52
22K
R53
10K
IC9
IN
1
OUT
3
GND 2
C10
25V100
µ
C11
0.1
C12
25V100
µ
C13
0.1
IN
1
OUT
3
GND 2
C14
50V1
µ
R14
1.2K
R15
6.8K
VREF
CN1
2
1
3
C78
1000P
C79
1000P
R119
0
R120
0
R118
47K
R117
47K
R54
4.7K
C63
50V10
µ
IC7
1
2
3
45
6
7
8
C82
6.3V100
µ
C83
6.3V100
µ
-5V
R121
100
D129
D128
D127
D126
D125
D124
D130
IC12
7
14
C2
50V2.2
µ
R111
100K
C106
6.3V100
µ
C107
6.3V100
µ
R113
68
R134
33
R126
22K
R125
22K
R124
22K
R123
22K
C111
0.1
R115
33
R127
1K
R128
1K
R129
47K
Q24
R130
220
SW1
3
1
2
Q13
Q14
Q15
Q16
Q17
Q18
Q12
Q11
Q10
Q7
Q6
Q5
Q4
Q3
Q8
Q9
D104
D105
D103
D108
D121
D116
D111
D119
D110
D120
D123
D114
D113
D118
D112
D100
D107
D106
D101
D122
D115
D102
D117
D109
IC11
7
10
9
8
IC11
12
5
4
3
IC11
6
11
-5V
+5V(V2)
+5V(V1)
+5V(V2)
+5V(V1)
+5V(V1)
+5V(V1)
+5V(V1)
+5V(V1)
+5V(V1)
+5V(V2)
+5V(V1)
+5V(V2)
+5V(V1)
+5V(V1)
+5V(V2)
+5V(V1)
+5V(V1)
R116
0
+5V(V1)
C77
C76
C112
C113
C110
C20
R112
C114
C67
C1
C2
45
C1
44
C0
43
R9
59
INT1
12
D3
2
D2
3
D1
4
IOR
10
INT0
11
C5
48
C4
47
PI
61
EP3
16
RESET
63
A0
7
IO
W
9
D0
5
A1
6
R5
55
R6
56
R7
57
R8
58
C3
46
R4
54
R0
50
R1
51
R2
52
R3
53
RXB
39
RXA
38
TXB
41
TXA
40
OSO
34
OSI
33
SXO
21
SR1
20
EP2
15
CK2M
18
NI
62
SR0
19
VDD
1
VDD
31
VDD
49
GND
17
GND
35
GND
64
CSN
8
N.C
32
N.C
42
N.C
60
EP0
13
EP1
14
IP0
27
IP1
28
IP2
29
IP3
30
OP0
23
OP1
24
OP2
25
OP3
26
CK16M
36
CK512K
37
CK2K
22
R27
1K
C18
8P
X1
16.384M
C19
47P
R28
1M
0.1
C17
+5V(V1)
R160
100K
L5
L10
0
L12
33
L13
33
L14
33
L15
33
L16
33
L17
33
R144
33
R150
33
R151
33
R152
33
R153
33
R145
33
R146
33
R147
33
R148
33
R149
33
L4
3
2
41
L11
0
L6
R141
270
R136
0
R137
Q32
SW301
2
JOG[2]
1
JOG[1]
3
GND
CN301
2
1
3
J17
0
C66
1000P
C65
1000P
JP1
JP6
JP2
JP8
JK1
4H
1L
3T
2R
JP7
0
JP3
0
JP5
0
JP4
JP16
0
CN5
1G
2R
3B
4W
INT[1]
R[12]
R[13]
INT[2]
IOR
IO
W
R[20]
R[21]
R[22]
R[23]
CO24
G
R
R
G
CO23
CO22
R
G
CO21
R
G
R
CO20
G
R
G
CO19
R
G
CO17
CO16
R
R
G
CO13
CO15
R
GG
R
CO18
R
GG
CO14
R
G
CO9
R
CO11
R
CO10
CO12
GG
G
CO8
G
CO7
R
G
R
R
R
CO4
G
R
CO6
R
CO2
G
G
G
G
R
CO1
G
R
R
CO3
CO5
MW
AU
T
O
MUTE
FWD
CONF
SP
ICM
1AP:PSUP1177Z
3AP:PSUP1196ZA
(6)
(2)
(7)
(8)
(5)
(4)
(3)
(1)
1
CD
2
FC2
3
FC1
4
Vin
5
VO
1
6
VCC
7
GND
8
VO
2
C25
47P
C26
8P
X2
12.288M
JK2
3
SP
2
1
MIC
4
R29
560
AG
C28
0.33
R30
150
R31
10K
R32
91K
C31
0.33
R36
2.2K
R40
2.2K
R39
220K
C33
0.1
C35
6.3V47
µ
AG
4
R38
2.2K
AG
3
C36
50V10
µ
IC12
1
2
13
R60
150
C43
0.047
R35
8.2K
R57
120K
R56
39
C39
470
µ
AG
C42
50V1
µ
R58
560K
R78
30K
R77
68K
R76
6.8K
C50
50V1
µ
R75
5.6K
R74
2.7M
C51
50V1
µ
C52
25V4.7
µ
C53
0.068
R70
4.7K
C86
0.047
C47
0.1
C48
0.015
C49
0.047
R71
0
C61
6.3V1000
µ
R69
3.3
R55
27K
C55
50V1
µ
C81
6.3V22
µ
C58
6.3V100
µ
C56
6.3V47
µ
C57
6800P
R63
18K
R64
12
R65
150K
Q22
R79
56K
AG
R80
27K
Q21
R81
120K
Q20
R82
220K
Q19
R66
12K
R62
2.2K
C45
0.22
AG
R61
100K
Q26
AG
IC12
98
6
IC12
34
5
AG
R34
1M
R43
1K
R42
10K
Q31
R59
3.3K
C46
0.1
R73
100K
C60
6.3V100
µ
R122
10K
C38
6.3V47
µ
R37
2.2M
C34
6.3V47
µ
R72
5.6K
IC4
1
RR
2
RT
X
3
TX1
4
TX0
5
TL1
6
TL0
7
TRL
8
RLO
9
MCI
10
MCO
11
CP1
12
N.C
13
CP2
14
KDI
15
SKG
16
SK
O
17
V+
18
AC
C
19
CS
20
SKI
21
VCC
22
VB
23
V-
24
XDC
25
VLC
26
AC
I
27
N.C
28
RXO
29
RXI
30
PRX
R135
33
C119
0.1
C118
0.1
C117
0.1
C27
0.1
AG
C120
6.3V47
µ
µ
AG
2
C22
0.1
C21
0.1
C23
47
µ
IC2
D5V1
15
DG1
12
D5V2
31
DG2
28
P/-S
10
TEST
45
RXD
22
TXD
23
BCLK
25
HCLK
26
OSC1
29
APMN
60
APNP
1
APNO
59
H1
47
SPO
8
AP1MN
55
AP1MP
56
AP1MO
54
M1
49
AP2MO
52
AP2MI
53
VREFM
57
VBB
48
OP7
21
OP6
20
OP5
19
OP4
18
OP3
17
OP2
16
OP1
14
OP0
13
RESET
11
-CE/-DOE
32
A5V1
6
AG
1
3
A5V2
7
AG
2
9
A5V3
46
AG
3
50
A5V4
51
AG
4
58
OSC2
30
ALE
33
-INT
44
-WR/STB
34
-RD/SDO
35
D6/SD1
37
D5/WBR
38
D4/OPC
39
D3/OPB
40
D2/OP
A
41
D1/OP9
42
D0/OP8
43
D7/SFT
36
HO-
5
HO+
4
VREFD
A
2
-FSYNC
24
R133
10
IC12
10
11
12
C59
0.1
+5V(V2)
R67
2.2K
C32
6.3V22
µ
AG
+5V(V2)
+5V(V2)
R68
2.2K
C89
6.3V22
µ
AG
+5V(V1)
+5V(V1)
+5V(V2)
+5V(V2)
R138
100K
C84
6.3V22
C37
6.3V22
µ
C116
C24
D22
JP14
JP15
C44
D2
C54
L7
0
L9
L8
0
C122
150P
C108
470P
C121
0.47
C40
680P
CN3
1
2
CN4
1
2
C41
0.33
C85
0.068
C30
D
C
B
A
D
C
B
A
D[11]
D[9]
D[12]
R[1]
D[10]
R[2]
R[3]
D[5]
SP
MIC
Summary of Contents for KX-T7456 - Digital 24 Button Speakerphone Display
Page 4: ...4 DISASSEMBLY INSTRUCTIONS 4 1 HOW TO REMOVE THE LOWER CABINET Procedure 1 4 ...
Page 8: ...5 IC DATA 5 1 IC1 8 ...
Page 11: ...11 ...
Page 15: ...15 ...
Page 20: ...7 4 DATA COMMUNICATION CIRCUIT 1 Function 20 ...
Page 24: ...The reset signal is negledted 24 ...
Page 29: ...8 TROUBLESHOOTING GUIDE 8 1 NO OPERATION 8 2 THE LCD DOES NOT OPERATE 29 ...
Page 31: ...8 5 SPEAKER PHONE TROUBLE 8 6 TONE DIAL TROUBLE 8 7 TROUBLE OF OHCA 31 ...
Page 32: ...8 8 HANDSET TROUBLE 9 TERMINAL GUIDE OF ICS TRANSISTORS AND DIODES 32 ...
Page 36: ...12 CABINET AND ELECTRICAL PARTS LOCATION 13 ACCESSORIES AND PACKING MATERIALS 36 ...
Page 49: ...33 37 34 35 36 25 32 ...
Page 55: ...SW301 CN301 1 2 3 ...
Page 57: ...1 5 2 6 3 7 4 8 ...
Page 58: ...9 13 10 14 11 15 12 16 ...
Page 59: ...17 21 18 22 19 23 20 24 ...