KX-TEA308NE
© 2005 Panasonic Communicat ions Co., Ltd. All
rights reserved. Unauthorized copying and
distribution is a violation of law.
KX-TEA308NE
KX-TE82460NE
KX-TE82492NE
KX-TE82493NE
KX-A227X
(for Europe)
Advanced Hybrid System
IMPORTANT INFORMATION ABOUT LEAD FREE, (PbF), SOLDERING
If lead free solder was used in the manufacture of this product the printed circuit boards will be marked PbF.
Standard leaded, (Pb), solder can be used as usual on boards without the PbF mark.
When this mark does appear, please read and follow the special instructions described in this manual on the use of PbF and how
it might be permissible to use Pb solder during service and repair work.
ORDER NO. KMS0507104CE
1 ABOUT LEAD FREE SOLDER (PbF: Pb free) 4
1.1. SUGGESTED PbF SOLDER
4
1.2. HOW TO RECOGNIZE THAT Pb FREE SOLDER IS
USED
5
2 FOR SERVICE TECHNICIANS
7
3 CAUTION
8
3.1. SAFETY PRECAUTIONS
8
3.2. INSULATION RESISTANCE TEST
8
3.3. BATTERY CAUTION
8
3.4. CAUTION
8
4 SPECIFICATIONS
9
4.1. GENERAL DESCRIPTION
9
4.2. CHARACTERISTICS
9
4.3. SYSTEM CAPACITY
9
5 SYSTEM OVERVIEW
10
5.1. SYSTEM COMPONENTS
10
5.2. SYSTEM CONNECTION DIAGRAM
11
6 NAMES AND LOCATIONS
12
7 CONNECTION
12
7.1. SERIAL INTERFACE CONNECTION
12
8 DISASSEMBLY INSTRUCTIONS
13
8.1. DISASSEMBLY INSTRUCTION
13
9 BLOCK DIAGRAM
15
9.1. SYSTEM BLOCK DIAGRAM
15
9.2. POWER BLOCK DIAGRAM
16
9.3. KX-TEA308NE MAIN BLOCK DIAGRAM
16
9.4. KX-TEA308NE CO BLOCK DIAGRAM
17
9.5. KX-TEA308NE POWER SUPPLY UNIT BLOCK
DIAGRAM
17
10 EXPLANATION OF BLOCK DIAGRAM
18
10.1. MAIN UNIT (KX-TEA308NE)
18
11 CIRCUIT OPERATION
20
11.1. POWER SUPPY CIRCUIT
20
11.2. CO INTERFACE CIRCUIT
21
11.3. CROSS POINT SWITCH CIRCUIT
26
11.4. INTERCOM CIRCUIT
28
11.5. POWER FAILURE THROUGH CALL SWITCHING
CIRCUIT
29
11.6. DATA COMMUNICATION CIRCUIT
29
11.7. CONTROL CIRCUIT
31
11.8. TONE GENERATOR CIRCUIT
31
11.9. DTMF GENERATOR CIRCUIT
32
11.10. DTMF RECEIVER CIRCUIT
32
11.11. INT CALLID INTERFACE CIRCUIT
33
11.12. MODEM INTERFACE CIRCUIT
33
11.13. USB INTERFACE CIRCUIT
34
11.14. OGM INTERFACE CIRCUIT
34
11.15. RINGING SIGNAL GENERATO R CIRCUIT
35
11.16. SMDR INTERFACE CIRCUIT
35
11.17. DOORPHONE CARD INTERFACE (KX-TE8246 0NE)
36
11.18. BUILT IN VOICE MESSAGE CARD INTERFACE (KX-
TE82492NE)
36
11.19. CALL ID CARD INTERFACE (KX-TE82493NE)
37
12 TROUBLESHOOTING GUIDE
38
12.1. NO OPERATION (Check POWER SUPPLY BOARD,
MAIN BOARD and 2AP BOARD)
38
12.2. NO DIAL TONE
39
12.3. CANNOT DIAL
40
12.4. CANNOT CALL EXTENSION
41
12.5. CANNOT USE PROPRIETA RY TELEPHONE
41
12.6. CANNOT RECEIVE INCOMING CALL
41
12.7. CANNOT SEND DTMF DIALING
42
12.8. CANNOT RECEIVE CALL DIAL TONE
42
12.9. CANNOT SEND A HOLD ON MUSIC
43
13 IC DATA
44
13.1. IC700
44
13.2. IC7
46
13.3. IC8
46
14 TERMINAL GUIDE OF ICS, TRANSISTORS AND DIODES
47
15 HOW TO REPLACE A FLAT PACKAGE IC
48
15.1. PREPARATION
48
15.2. REMOVAL PROCEDURE
48
15.3. INSTALLATION PROCEDURE
48
15.4. REMOVING SOLDER FROM BETWEEN PINS
48
16 FIXTURES AND TOOLS
49
17 CABINET AND ELECTRICAL PARTS LOCATION
50
18 ACCESSORIES AND PACKING MATERIALS
51
19 REPLACEMENT PARTS LIST (KX-TEA308NE)
52
19.1. CABINET AND ELECTRICAL PARTS
52
19.2. ACCESSORIES AND PACKING MATERIALS
52
19.3. MAIN BOARD PARTS
52
19.4. CO BOARD PARTS
59
19.5. POWER SUPPLY BOARD PARTS
62
19.6. FIXTURES AND TOOLS
63
20 FOR THE SCHEMATIC DIAGRAM
64
21 SCHEMATIC DIAGRAM (KX-TEA308NE)
66
21.1. MAIN No.1 (Extention A-D Block)
66
21.2. MAIN No.2 (Extention E-H Block)
70
21.3. MAIN No.3 (Cross-Point Block)
74
21.4. MAIN No.4 (ASIC, Memory Block)
78
21.5. MAIN No.5 (CO Block)
82
21.6. POWER SUPPLY
86
22 PRINTED CIRCUIT BOARD (KX-TEA308NE)
87
22.1. MAIN BOARD
87
22.2. CO BOARD
89
22.3. POWER SUPPLY
91
23 KX-TE82460NE (2-PORT DOORPHONE CARD)
92
23.1. HOW TO RECOGNIZE THAT Pb FREE SOLDER IS
USED
93
23.2. LOCATION OF OPTIONAL CARDS
94
CONTENTS
Page Page
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KX-TEA308NE
23.3. DOORPHONE/DOOROPENER CARD BLOCK DIAGRAM
95
23.4. EXPLANATION OF BLOCK DIAGRAM/CIRCUIT
OPERATIONS
95
23.5. TROUBLESHOOTING GUIDE
96
23.6. IC DATA
97
23.7. TERMINAL GUIDE OF ICS, TRANSISTORS AND
DIODES
98
23.8. ACCESSORIES AND PACKING MATERIALS
98
23.9. REPLACEMENT PARTS LIST (KX-TE82460NE)
99
23.10. FOR THE SCHEMATIC DIAGRAM
101
23.11. SCHEMATIC DIAGRAM (KX-TE8246 0NE)
102
23.12. PRINTED CIRCUIT BOARD (KX-TE8246 0NE)
104
24 KX-TE82492NE (2-CHANNEL VOICE MESSAGE CARD)
105
24.1. HOW TO RECOGNIZE THAT Pb FREE SOLDER IS
USED
106
24.2. LOCATION OF OPTIONAL CARDS
107
24.3. BLOCK DIAGRAM
108
24.4. CIRCUIT OPERATIONS
109
24.5. TROUBLESHOOTING GUIDE
110
24.6. IC DATA
112
24.7. TERMINAL GUIDE OF ICS, TRANSISTORS AND
DIODES
113
24.8. ACCESSORIES AND PACKING MATERIALS
113
24.9. REPLACEMENT PARTS LIST (KX-TE82492NE)
114
24.10. FOR THE SCHEMATIC DIAGRAM
115
24.11. SCHEMATIC DIAGRAM (KX-TE8249 2NE)
116
24.12. PRINTED CIRCUIT BOARD (KX-TE8249 2NE)
118
25 KX-TE82493NE (3-PORT CALLER ID CARD)
119
25.1. HOW TO RECOGNIZE THAT Pb FREE SOLDER IS
USED
120
25.2. LOCATION OF OPTIONAL CARDS
121
25.3. BLOCK DIAGRAM
122
25.4. CIRCUIT OPERATIONS
122
25.5. TROUBLESHOOTING GUIDE
123
25.6. IC DATA
124
25.7. TERMINAL GUIDE OF ICS, TRANSISTORS AND
DIODES
126
25.8. ACCESSORIES AND PACKING MATERIALS
126
25.9. REPLACEMENT PARTS LIST (KX-TE82493NE)
127
25.10. FOR THE SCHEMATIC DIAGRAM
129
25.11. SCHEMATIC DIAGRAM (KX-TE8249 3NE)
130
25.12. PRINTED CIRCUIT BOARD (KX-TE8249 3NE)
132
26 KX-A227X (BACK-UP BATTERY CABLE)
133
26.1. ACCESSORIES AND PACKING MATERIALS
134
26.2. REPLACEMENT PARTS LIST (KX-A227X)
135
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KX-TEA308NE
1 ABOUT LEAD FREE SOLDER (PbF: Pb free)
Note:
In the informa tion below, Pb, the symbol for lead in the periodic table of elements, will refer to standard solder or solder that
contains lead.
We will use PbF solder when discussing the lead free solder used in our manufa cturing process which is made from Tin, (Sn),
Silver, (Ag), and Copper, (Cu).
This model, and others like it, manufa ctured using lead free solder will have PbF stamped on the PCB. For service and repair
work we suggest using the same type of solder although, with some precautions, standard Pb solder can also be used.
Caution
•
• •
• PbF solder has a melting point that is 50° ~ 70° F, (30° ~ 40°C) higher than Pb solder. Please use a soldering iron with
temperature control and adjust it to 700° ± 20° F, (370° ± 10°C). In case of using high temperature soldering iron, please
be careful not to heat too long.
•
• •
• PbF solder will tend to splash if it is heated much higher than its melting point, approximately 1100°F, (600°C).
•
• •
• If you must use Pb solder on a PCB manufactured using PbF solder, remove as much of the original PbF solder as possible
and be sure that any remaining is melted prior to applying the Pb solder.
•
• •
• When applying PbF solder to double layered boards, please check the component side for excess which may flow onto the
opposite side (See figure, below).
1.1. SUGGESTED PbF SOLDER
There are several types of PbF solder available commercially. While this product is manufactured using Tin, Silver, and Copper,
(Sn+Ag+Cu), you can also use Tin and Copper, (Sn+Cu), or Tin, Zinc, and Bismuth, (Sn+Zn+Bi). Please check the
manufacturer’s specific instructions for the melting points of their products and any precautions for using their product with other
materials.
The following lead free (PbF) solder wire sizes are recommended for service of this product: 0.3mm, 0.6mm and 1.0mm.
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KX-TEA308NE
1.2. HOW TO RECOGNIZE THAT Pb FREE SOLDER IS USED
5
KX-TEA308NE
6
KX-TEA308NE
2 FOR SERVICE TECHNICIANS
ICs and LSIs are vulnerable to static electricity.
When repairing, the following precautions will help prevent recurring malfunctions.
1. Cover the plastic parts boxes with aluminum foil.
2. Ground the soldering irons.
3. Use a conductive mat on the worktable.
4. Do not touch IC or LSI pins with bare fingers.
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KX-TEA308NE
3 CAUTION
3.1. SAFETY PRECAUTIONS
1. Before servicing, unplug the power cord to prevent an electric shock.
2. When replacing parts, use only the manufacturer´s recommended components for safety.
3. Check the condition of the power cord. Replace if wear or damage is evident.
4. After servicing, be sure to restore the lead dress, insulation barriers, insulation papers, shields, etc.
5. Before returning the serviced equipment to the customer, be sure to perform the following insulation resistance test to prevent
the customer from being exposed to shock hazards.
3.2. INSULATION RESISTANCE TEST
1. Unplug the power cord and short the two prongs of the plug with a jumper wire.
2. Turn on the power switch.
3. Measure the resistance value with ohmmeter between the jumpers AC plug and each exposed metal cabinet part, such as
screw threads, control shafts, handle brackets, etc.
Note:
Some exposed parts may be isolated from the chassis by design. These will read infinity.
4. If the measurement is outside the specified limits, there is a possibility of shock hazard. The equipment should be repaired and
rechecked before it is returned to the customer.
3.3. BATTERY CAUTION
1. Danger of explosion if battery is incorrectly replaced. Replace only with the same or equivalent type recommended by the
manufacturer. Dispose of used batteries according to the manufacturer’s Instructions.
2. The lithium battery is a critical component (type No.CR23541). Please observe for the proper polarity and the exact location
when replacing it and soldering the replacement lithium battery in.
3.4. CAUTION
The power socket wall outlet should be located near this equipment and be easily accessible.
8
KX-TEA308NE
4 SPECIFICATIONS
4.1. GENERAL DESCRIPTION
Control Bus Original bus (16-bit, 24 MHz)
Switching Space Division CMOS Crosspoint Switch
Power Input 100 V AC to 240 V AC, 0.8A to 0.4A, 50 Hz/60Hz
External Battery +24 V DC (+12 V DC x 2)
Maximum Power Failure Tolerance 300 ms (without using backup batteries)
Memory Backup Duration 7 years
Dialling Outside (CO) Line Pulse (10 pps, 20 pps) or Tone (DTMF)
Extension Pulse (10 pps, 20 pps) or Tone (DTMF)
Intercom Path 3
Mode Conversion Pulse-DTMF
Ring Frequency 20 Hz/25 Hz (selectable)
Operating Environment Temperature 0°Cto40°C
Humidity 10 % to 90 % (non-condensing)
Conference Call Outside (CO) Line 2
Music on Hold (MOH) 1 port
Selectable MOH: Internal/Exte rnal/Tone
Paging Internal 1
Extension 1 port
Serial Interface Port RS-232C 1
USB 1.1 1
Extension Connection Cable SLT 1 pair wire (T, R)
PT 2-pair wire (T, R, H, L)
DSS Console 1-pair wire (H, L)
Dimension 249 mm (W) x 316 mm (H) x 73 mm (D)
Weight (when fully expanded) Approx. 1.8 kg
4.2. CHARACTERISTICS
Terminal Equipment Loop Limit PT 40 Ω
SLT 600 Ω including set
Doorphone 20 Ω
Minimum Leakage Resistance 15000 Ω minimum
Maximum Number of Extension
Instruments per Line
1 PT or SLT in standard connection
1 PT and 1 SLT in parallel connection
Ring Voltage 65 Vrms at 20 Hz/25 Hz depending on the ringing load
Outside (CO) Line Loop Limit 1600 Ω maximum
Hookswitch Flash/Recall Timing Range 24 ms-2032 ms
Door Opener Current Limit 30 V DC/30 V AC, 3 A maximum
Paging Terminal Impedance 600 Ω
MOH Terminal Impedance 10000 Ω
4.3. SYSTEM CAPACITY
4.3.1. System Capacity
KX-TEA308
Basic System Outside (CO) line 3
Extensions for PT/SLT 8
9
KX-TEA308NE
4.3.2. Maximum Cards Terminal Equipment
ltem KX-TEA308
PT 8
SLT 8
2-Port Doorphone Card 1
3-Port Caller ID Card 1
2-Channel Voice Message Card 1
Doorphone 2
Door Opener 2
Pager 1
Music on Hold (MOH) 1
DSS Console 2
4.3.3. System Data
ltem Max. Quantity
Operator 1
System Speed Dialling 100
One-touch Dialling 24 per extension (PT)
Personal Speed Dialling 10 per extension
Call Park Area 10
Absent Message 6
Toll Restriction (TRS) COS 5
Extension Group 8
Message Waiting 8 per extension
Message for Built-in Voice Message 125 messages (total 60 minutes)
5 SYSTEM OVERVIEW
5.1. SYSTEM COMPONENTS
Model Description
Main Unit KX-TEA308NE Advances Hybrid System: 3 Outside (CO) Line, 8 Hybrid Extentions
Optional Service Cards KX-TE82460NE
KX-TE82492NE
KX-TE82493NE
2-Port Doorphone Card
2-Channel Voice Message Card
3-Port Caller ID Card
Proprietary Equipment KX-T30865
KX-A227X
Doorphone
Backup Battery Cable
10
KX-TEA308NE
5.2. SYSTEM CONNECTION DIAGRAM
•
• •
• Connect a display-equipped proprietary telephone (PT) to extension jack 01, as this extension is automatically designated as
the manager extension.
11
KX-TEA308NE
6 NAMES AND LOCATIONS
7 CONNECTION
7.1. SERIAL INTERFACE CONNECTION
12
KX-TEA308NE
8 DISASSEMBLY INSTRUCTIONS
8.1. DISASSEMBLY INSTRUCTION
1. Pull the slide button (arrow 1) to the right and, holding it, slide the
cable cover upwards (arrow 2).
2. Then turn the cable cover slightly to remove it.
3. Remove the three screws (A).
4. Holding the protrusions on both sides of the front cover, swing the
cover open.
5. Holding the front cover open at about a 45° angle, remove the front
cover by pushing it in the direction of the arrow as shown on the right.
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KX-TEA308NE
5. Remove the 1 screws (A).
6. Remove the power supply board cover.
7. Pull out the 4 connectors.
8. Remove the 2 screw (B) and 1 screw (A).
9. Remove the power supply board.
10. Remove the 2 screw (B).
11. Remove the CO board.
12. Pull out the 1 connector.
13. Remove the 2 screws (A) and 1 screw (B).
14. Remove the main board.
Procedure:
•
• •
• Insert the SW CABLE into AC POWER SWICH.
Caution:
•
• •
• Be sure each colored wire is inserted to the correct lug (very important).
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KX-TEA308NE
9 BLOCK DIAGRAM
9.1. SYSTEM BLOCK DIAGRAM
15
KX-TEA308NE
9.2. POWER BLOCK DIAGRAM
9.3. KX-TEA308NE MAIN BLOCK DIAGRAM
KX-TEA308NE 1AP BLOCK DIAGRAM
Host i/f
Q1-4,TOE1,2,STD1,2
TONE
25Hz
CROSS
POINT
ROM
SRAM
DTMFR(1,2)
(For EXT)
PIO
ASIC
BELL
TONE
(I/O)HOOK1-8,BELL1-8
620,440,350Hz
CO CID
CONNECTOR
D-Sub
POWER UNIT
CONNECTOR
USB
CO1-3
EXT1-8
I/O,DTMFG
BGM
PAG E
CO
(2AP)
Card
CONNECTOR
ASIC
8086
DSP
P I O
APT i/f
BV Card
CONNECTOR
TAM1-2,TONE
(APT i/f)PRX,PTX,PTXE1-3
(UART)RXD,TXD
EXT1
EXT2
EXT3
EXT4
EXT5
EXT6
EXT7
EXT8
Ringer
Circuit
Door Phone
Door Opener
CONNECTOR
DOOR1,2
Int CID(FSK,DTMF)
OGM,Modem
CN708
CN707
CN701
CN706
CN710
CN704
CN703
IC601
IC602
IC603
IC705
IC704
IC700
IC7, IC8
IC606, IC607
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KX-TEA308NE
9.4. KX-TEA308NE CO BLOCK DIAGRAM
9.5. KX-TEA308NE POWER SUPPLY UNIT BLOCK DIAGRAM
KX-TEA308NE POWER SUPPLY UNIT BLOCK DIAGRAM
AC IN
L
FUSE
Surge
Protector
Noise
Control
Over
Current
Detection
Circuit
Filter
Rectifier
Primary Secondary
&
Smoother
Rectifier
Voltage
Detection
&
Smoother
N
FG
Battery
+24
V
+27V
+15V
GND
GND
SW
Back-up
Adaptor
DC-DC
Converter
+3.3V
DC-DC
Converter
CN1
F1
Z1
L1
D10 ~ D13
C5
IC1
PC1
Q1
R30, R31
D101, C101
IC101
RL501
Q503
IC201
IC301
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KX-TEA308NE
10 EXPLANATION OF BLOCK DIAGRAM
10.1. MAIN UNIT (KX-TEA308NE)
10.1.1. Power Supply Circuit
This power supply unit is a switching power supply. Power supply unit supplies DC voltage (+27V,+15V,3.3V) to main board and
other optional cards. And this unit has an adaptor circuit to back up battery.
10.1.2. COL Interface Circuit
There are the interface circuits linking the CO line (CO1 -CO3) and the cross point circuit section.
10.1.3. Cross Point Circuit
This is a space division switching system for connecting the following:
The eight extension circuits with the three CO, DTMF generator, DTMF receiver, INT-CALL ID, MODEM, OGM, BV, paging, music
on hold, tone etc.
It is composed of 3 C-MOS IC´s. (8 X 16 matrix: 1pcs and 4 X 8 matrix: 2pce).
10.1.4. Intercom Circuit
This is the interface circuit of the single line telephone, and it is composed of 8 intercom circuit (ICM1-8).
10.1.5. Power Failure Through Call Switching Circuit
There is one power failure transfer circuit (CO1-EXT101).
10.1.6. Data Communication Circuit
The APT i/f module which performs communication with a private telephone machine is built in ASIC.
10.1.7. Control Circuit
A control block consists of CPU (compatibility with Intel 8086) (IC700), Flash ROM (8Mbit) (IC705) and SRAM (4Mbit) (IC704).
RTC, Timer, DMAC, USB Controller, WDT, INTC, UART, General Purpose I/O ports, APT i/f and DSP are built into CPU chip.
General purpose I/O block is composed by discrete parts (IC7, IC8) and the I/P port in CPU.
IC7 and IC8 control extension, and the I/O ports in CPU control the COL chiefly.
In order to maintain time, system data and others, RTC (Real Time Clock) in CPU and SRAM are backed up with the lithium battery.
10.1.8. Tone Generator Circuit
The rectangle wave generated by the timer of CPU is changed into sine wave with a low pass filter, and various tones are
generated.
10.1.9. DTMF Generator Circuit
DTMF (Dial Tone Multi Frequency) generator is used for dispatch to outside line, and communication with the voice mail connected
to the extension.
10.1.10. DTMF Receiver Circuit
The circuit that receives the Dial Tone Multi Frequency by which extension dispatch is carried out with the DTMF receiver
connected to the crossing point.
10.1.11. Int Call ID Circuit
FSK/DTMF generated by DSP in CPU are connected even to a crossing point through AMP. The circuit which sends out a CALLID
signal to the telephone connected to an extension by connecting the line of INT-CALL-ID with arbitrary extensions.
10.1.12. Modem Circuit
The MODEM signal generated by DSP in CPU is connected even to a crossing point through AMP.
The circuit, which connects the line of MODEM with arbitrary outside line, and enables MODEM communication with outside line.
10.1.13. USB Circuit
The circuit which makes communication possible by PC and 1.1 standards by the USB controller in CPU.
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KX-TEA308NE
10.1.14. OGM Circuit
The 4M Serial Flash ROM is connected to CPU by the memory controller in DSP (in CPU).
A maximum of 3-minute storing of OGM is possible to a serial flash ROM.
10.1.15. Ring Signal Generator Circuit
This section generates the ring signal for the single line telephone. A 20/25Hz square wave is generated by the CPU timer and sent
to low pass filter and the Ring signal is amplified by BELL amplifier circuit, and then passed it through the ringing signal switching
relay to the single line telephone.
10.1.16. SMDR Interface Circuit
This is the RS232C interface port. When the port is connected to a printer. The port can be used to output the SMDR feature
recording messages and the contents of the system program.
10.1.17. Door Phone Interface
An doorphone card interface consists of two intercom paths connected to a crossing point, and address data and CS signals.
10.1.18. Call ID Interface
A CALLID card interface consists of three CALLID signal lines from outside line, and address data and CS signal.
10.1.19. BV Interface
BV card interface consists of two BV telephone call paths connected to a crossing point, and address data and CS signals.
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KX-TEA308NE
11 CIRCUIT OPERATION
11.1. POWER SUPPY CIRCUIT
11.1.1. The function of the power unit are listed below
AC-DC Inverter Function This function isolates and converts the AC input voltage to DC
input and output of DC27V.
DC-DC Converter Function This function outputs DC+15V and 3.3V from the inputted
DC27V.
Battery Back Up Adaptor Function This function connects battery and service unit without battery
adaptor, only needs a cable connected to the battery and
service unit.
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KX-TEA308NE
11.1.2. Control Section
1) AC-DC Inverter Function
The AC input voltage is rectified and smoothed by D10-13 and C5. The obtained DC voltage is converted into a rectangular wave
by the switching transistor Q1, then isolated and transduced by T1. This converted rectangular wave is rectified and smooth ed by
D101 and C101 to output DC27V. The DC27V is transmitted to the primary side by PC1 and then PWM- controlled to keep
constant. The switching frequency of Q1 is approximately 60KHz.
2) DC-DC Inverter Function
The DC 27V DC is converted into a rectangular wave by control IC201, and then output as an output voltage of +15V by the
smoothing circuit which is composed of D201, L201, C201.
The 27V DC is converted into rectangular wave by control IC301 and then output as an output voltage of +3.3V by the smoothing
circuit which is composed of D301, L301, C301.
3) Battery back up function
This back up battery adaptor circuit has DC supply function, from battery (+24V) to service unit and DC charge from service unit
to battery (+24V). Charge current is typ. 0.3A.
11.2. CO INTERFACE CIRCUIT
11.2.1. Composition
This is composed of the following circuit:
1) Bell signal detection
2) DC loop formation circuit
3) Pulse dial transmission circuit
4) CALL ID interface circuit
5) COL bidirectional amplifie r circuit
1) Bell signal detection
When CO line is idle, photo coupler PC1, PC2 are OFF.
When there is an incoming signal from CO line, the current flows PC1 as in the following way.
Tip → L1 → R2 → PC1(1-2) → C3 → R5 → L1 → Ring: This cause pin4 of PC1 to change the level from High to low.
Ring → L1 → R5 → C3 → PC2(1-2) → R2 → L1 → Tip: This cause pin4 of PC2 to change the level from High to low.
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KX-TEA308NE
2) DC loop formation circuit
In the off hook status, PC5 is ON.
DC loop path:
Tip→L1→D1→D2→D3→Q10(E-C)→Q1(C-E)→R9→R8→D3→L1→Ring
At this time, the output of the photo coupler PC1 changes level from High to low.
Ring→L1→D3→Q10(E-C)→Q1(C-E)→R9→R8→D3→D2→D1→L1→Tip
At this time, the output of the photo coupler PC2 changes level from High to low.
Afterwards, CPU monitor this change (low level to high level). If the high level continues for a specified time set by system data
programming. CPU assumes that CO line has become On hook status. And the CO line circuits is restored to the idle status.
3) Pulse dial transmission circuit
When the Off hook status, pulse dial transmission is executed by alternating On hook and Off hook. The status of On hook or
Off hook is controlled by the switching transistor Q10.
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KX-TEA308NE
4) CALL ID interface circuit
It is insulated by the capacitors in a COL circuit, and the call ID signal inputted from outside line is transmitted to a CALLID
option card.
The flow of a CALLID signal
Tip→L1→C29→R54→IC4
Ring→L1→C29→R55→IC4
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KX-TEA308NE
5) COL Bidirectional Amplifier circuit
This circuit consists of bidirectional amplifier function for communication between the extensions and COL, returns loss
compensation for conference, shunt function and mute function.
(Composition)
For transmitting signals from the extensions to COL, this circuit consists of R34, R35, R26, R27, R18, R29, C14, C15, C10, C16
and the operational amplifie r (IC1).
For transmitting signals from the COL to extensions, this circuit consists of R24, R25, R31, R28, R37, R30, C12, C13, C17, C18,
and the operational amplifie r (IC1).
COL side-tone suppression circuit which includes a balanced network BN1 consists of R22 R23, C11 and R16, R17, R20, R21.
EXT side-tone suppression circuit which includes a balanced network BN2 consists of R41, R42 and R40, R43, R38, R39.
Also extension side-tone suppression circuit which includes a balanced network BN3 consists of R45, R46 for supplementing
side-tone suppression during the conference commu nication.
The analog switch (IC2) is used for the following:
(1) Conference (Pin 6, 8 and 9)
(2) Shunt (Pin 12, 10 and 11)
(3) Mute (Pin 13, 1 and 2)
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1) Conference switch
Normally, pin 6 of the analog switch IC2 is low level, but during conferences, this pin becomes high level. Because, during
conferences, it should compensate the return loss by connecting the balance network BN2 and the balance network BN3 in
parallel.
2) Mute switch
The mute switch consists of pin 13, 1 and 2 of the analog switch(IC2). This switch has the following functions.
a) When a dial signal (DP) is sent to the COL, signals from the extensions are blocked.
b) When the hold on music is sent to the COL, signals from the extensions are blocked.
c) When the COL interface circuit is in the idle state, oscillation of COL bidirectional amplifier is inhibited. When pin 13 of IC2
changes to low level, the interval between pins 1 and 2 of the analog switch turns off, and signals are blocked.
3) Shunt switch
The shunt switch consists of pin 12, 10 and 11 of analog switch IC2.It is used to prevent the pulse dialing signal which is
transmitted to the extensions. When pin 12 of IC2 changes to high from low, the analog switch becomes ON (the interval
between pin 10 and 11), and GAIN of the COL cross point operational amplifie r becomes zero.
Shunt SW Mute SW Conference SW
pin no. of analog switch 12 13 6
No connection (idle) H (on) L (off) L (off)
Two party call L (off) H (on) L (off)
Conference L (off) H (on) H (on)
Hold on music transmission H (on) H (on) L (off)
Condition of COL interface amplifier circuit and analog switches.
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11.3. CROSS POINT SWITCH CIRCUIT
11.3.1. Composition
The cross point circuit composed of three cross point switch IC´s (IC601:8X16, IC602 and IC603:4X8).
1) Cross Point Switch IC Operation
The cross point SW (IC601) contains a 8X16 array of cross point switches along with a 7 to 128 line decoder and latch circuits.
Any one of the 128 switches can be addressed by selecting appropriate seven address bits. The selected switch can be turned
on or off by applying either logical one or zero to the DATA input. Chip select allows the cross point array to be cascaded for
matrix expansion.
The cross point SW´s (IC602, IC603) contain 4X8 array of cross point switches along with a 5 to 32 line decoder and latch
circuits. Any one of the 32 switches can be addressed by selecting appropriate five address bits. The selected switch can be
turned on or off by applying either logical one or zero to the DATA input. Chip select allows the cross point array to be cascaded
for matrix expansion.
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11.4. INTERCOM CIRCUIT
11.4.1. INTERCOM CIRCUIT
1) Composition
This is composed of the following circuits:
a) +15V power source for the extension telephones
b) Hook detect for SLT and pulse dialing detect
c) Bell ring trip section
2) Circuit operation
a) Power supply to the telephone
With the telephone off hook, a DC loop is formed, and current is supplied to the telephone. This circuit is limited to about 30mA
by Q200, Q202, R202, R204 and Q201, Q203, R203, R205.
+27V→R204→R202→Q200→RL201→telephone→RL201→Q201→R203→R205→AG
b) Hook detect for SLT and pulse dialing detect
When the telephone handset is taken off, DC loop is formed and the collector of U200 3,6 pin change to L from H.
And IC7 detects the off hook condition.
When the handset is replaced back on hook, the DC loop is interrupted and collector of U200 3,6 pin change to H from L and
EXT Pulse dialing is input either in the on hook or off hook condition, and the break number (on hook condition) is counted and
read as the dial number.
c) Bell ringing trip section
When the telephone is a signal line telephone, extension calling is executed by means of a ringing signal. When the ringing
signal is supplied, RL201 turns ON and the current flows are as follows:
Bell generation circuit → ringing signal line → RL201 → telephone → R206 → AG → Bell generation circuit
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11.5. POWER FAILURE THROUGH CALL SWITCHING CIRCUIT
11.5.1. Circuit operation
If an AC power failure lasts longer than one second (momentary power failure), the COL is directly connected to the extension.
The COL1 will be connected with EXT101.
11.6. DATA COMMUNICATION CIRCUIT
11.6.1. Composition
This circuit is composed of the ASIC and the data communication interface circuits for the ICM circuit.
11.6.2. Circuit Operation
1) Data Communication of CPU (IC700)
The APT i/f module is built into CPU.
An RX/TX couple signal is shared by eight APT communications; this communicates via the selection signal.
That is, in the APT i/f module, extension 1-8 port switch the port communicates every 4ms respectively with
#101→#102→#103→#104..... →#108→#101.....
When the extension is not connected with APT, it is recognized as an SLT connection and the dummy communication is
established.
Interface block diagram of CPU and ICM
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2) Data Communication of ASIC and PITS
When APT I/F Module in CPU send the request signal to the proprietary telephone and after receiving the key input information
(19 pulses) from the proprietary telephone and sending data (47 pulses) for LED control. APT I/F Module will receive
acknowledge signal from the proprietary telephone.
a) Reception
The data from the proprietary telephone is received via H and L lines along the path shown below.
H.L line → C208 → IC200 →T201 → R235 → Q210 → CPU
b) Transmission
The data to the proprietary telephone is transmitted along the following Path.
CPU → Q209 → Q215 → T201 → IC200 → C208 → H.L line
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