Panasonic KX-TDA6181X Service Manual

© 2005 Panasonic Communicat ions Co., Ltd. All
rights reserved. Unauthorized copying and
distribution is a violation of law.

KX-TDA6181X

(for Asia, Oceania, Middle Near East, Latin America,

Russia and Africa)

16-Port Analogue Trunk Card

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, Standa rd laded, (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. KMS0510155CE

1 ABOUT LEAD FREE SOLDER (PbF: Pb free) 3

1.1. SUGGESTED PBF SOLDER

3

1.2. HOW TO RECOGNIZE THAT Pb FREE SOLDER IS

USED

4

2 FOR SERVICE TECHNICIANS

5

3 GENERAL DESCRIPTIO N

5

4 SPECIFICATION

5

5 SYSTEM CONSTRUCTION

6

5.1. INSTALLING/REMOVING THE OPTIONAL SERVICE

CARDS

7

6 BLOCK DIAGRAM

14

7 CIRCUIT OPERATIONS

15

7.1. CONTROL-SYSTEM CIRCUIT

15

7.2. DESCRIPTION OF FUNCTIONS AND CIRCUITS

19

7.3. POWER SUPPLY CIRCUIT

22

8 TROUBLESHOOTING GUIDE

24

9 IC DATA

30

9.1. IC3 (ASIC)

30

9.2. IC6 (CODEC)

32

9.3. IC7 (CODEC)

33

9.4. IC9 (CODEC)

34

9.5. IC10 (CODEC)

35

9.6. IC601 (CPU) I/O MAP

36

10 HOW TO REPLACE A FLAT PACKAGE IC

37

10.1. PREPARATION

37

10.2. REMOVAL PROCEDURE

37

10.3. INSTALLATION PROCEDURE

37

10.4. REMOVING SOLDER FROM BETWEEN PINS

37

11 TERMINAL GUIDE OF ICs, TRANSISTORS AND DIODES

38

12 CABINET AND ELECTRICAL PARTS LOCATION

39

13 ACCESSORIES AND PACKING MATERIAL

40

14 REPLACEMENT PARTS LIST

41

14.1. CABINET AND ELECTRICAL PARTS LOCATION

41

14.2. ACCESSORIES AND PACKING MATERIALS

41

14.3. MAIN BOARD PARTS

41

15 FOR SCHEMATIC DIAGRAM

51

15.1. WAVEFORM

52

15.2. ELCOT16 BLOCK DIAGRAM

55

16 SCHEMATIC DIAGRAM

56

16.1. No.1

56

16.2. No.2

60

16.3. No.3

64

16.4. No.4

68

17 PRINTED CIRCUIT BOARD

70

17.1. COMPONENT VIEW

70

17.2. BOTTOM VIEW

71

CONTENTS

Page Page

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KX-TDA6181X

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, manufactured 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 manufa ctured 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.

3

KX-TDA6181X

1.2. HOW TO RECOGNIZE THAT Pb FREE SOLDER IS USED

4

KX-TDA6181X

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 part´s boxes with aluminum foil.

2. Ground the soldering irons.

3. Use a conductive mat on the worktable.

4. Do not touch the IC or LSI pins with bare fingers.

3 GENERAL DESCRIPTION

This card is inserted in the free slot of the TDA600 system and is capable of connecting 16 analog loop start lines.

Up to 2 CALLER ID/PAYTONE card can be added on as option cards.

The LPR is an SH-1 (SH7020) with 512Kbyte flash ROM and 128Kbyte SRAM, and supports software version upgrade though
downloading.

4 SPECIFICATION

Functional Block Functional contents

Analog External Line Interface Number of Ports 16 ports

Main Function +30V 30mA Feeding function

Dial Pulse Signal Transmission Function
DTMF Signal Transmission Function
Inversion Detection Function
Bell Detecting Function
Ring-off Signal Detection Function
2w/4w Conversion Function
Surge Protection Function
Returning Sound Generation Function
4ch CODEC Function

•

• •

• CODEC function

•

• •

• Power down function

•

• •

• µ/A Iaw switching function

•

• •

• Test function (Loop back, Tone generation)

•

• •

• Programmable digital filtering function

•

• •

• Serial interface function

•

• •

• PIO function

DTMF Generator Transmits arbitrary tones for every 16 line port
Option Card Can be installed two CO-CID/PT cards for eight lines
On-board DC/DC Power Supply Input +15V

Output +15V, +5V, +3.3V
Power Failure Forwarding Function Supports four lines
Self-diagnosis Function Performed with the extension interface in pairs

Channel Test, Dial Pulse Test, DTMF Test
ASIC#2 (eSAMSON) EC Bus interface function

H.100 Bus interface function, Digital PLL function

Local Bus interface function

Time Switch Function, Gain Control Function

Intelligent PIO Function, JTAG
Control Unit CPU SH-1/SH7020 (12.288MHz)

Flash ROM 512Kbyte

SRAM 128Kbyte
LED Display Circuit Card Status Display LED: 2-color (red/green)
External Interface Connector External Line Interface 50pin Amphenol Connector: 1 unit

Power Failure Transfer 4pin Modular Jack: 2 units

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KX-TDA6181X

5 SYSTEM CONSTRUCTION

6

KX-TDA6181X

5.1. INSTALLING/REMOVING THE OPTIONAL SERVICE CARDS

Slot Condition

Card Type Slot Type

KX-TDA600 KX-TDA620

Free 1-10 EMPR BUS-M Free 1-11 BUS-S
EMPR Card No Yes No No No
BUS-M Card No No Yes No No
BUS-S Card No No No No Yes
Trunk Cards Yes No No Yes No
Extension Cards Yes No No Yes No
OPB3 Card Yes No No Yes No
CTI-LINK Card Yes No No No No
EECHO Card Yes No No Yes No

Caution:

To protect the back board from static electricity, do not touch parts on the back board in the main unit and on the optional
service cards.To discharge static, touch ground or wear an earthing strap.

ELCOT16 Card

Function

16-port analogue trunk card with 4 power failure transfer (PFT) ports.

Accessories and User-supplied Items

Accessories (included): Screws X 2

User-supplied (not included): Amphe nol connector

7

KX-TDA6181X

Pin Assignments

Amphenol Connector

No. Signal Name Function No. Signal Name Function

1 RA Ring port 1 26 TA Tip port 1
2 RB Ring port 2 27 TB Tip port 2
3 RC Ring port 3 28 TC Tip port 3
4 RD Ring port 4 29 TD Tip port 4
5 RE Ring port 5 30 TE Tip port 5
6 RF Ring port 6 31 TF Tip port 6
7 RG Ring port 7 32 TG Tip port 7
8 RH Ring port 8 33 TH Tip port 8
9 RI Ring port 9 34 TI Tip port 9
10 RJ Ring port 10 35 TJ Tip port 10
11 RK Ring port 11 36 TK Tip port 11
12 RL Ring port 12 37 TL Tip port 12
13 RM Ring port 13 38 TM Tip port 13
14 RN Ring port 14 39 TN Tip port 14
15 RO Ring port 15 40 TO Tip port 15
16 RP Ring port 16 41 TP Tip port 16
17-25Reserved - 42-50Reserved -

LED Indications

Indication Color Description

CARD STATUS Green/Red Card status indication

OFF: Power Off
Green ON: Normal (all ports are idle)
Green Flash (60 times per minute ): Normal (a port is in use)
Red ON: Fault (includes reset)
Red Flash (60 times per minute): Out of Service

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KX-TDA6181X

In case of install CID/PAY8 on ELCOT16 card

Function

CID/PAY8: 8-port Caller ID signal type FSK/FSK (with Visual Caller ID)/DTMF, and 8 ports of Pay Tone Service (12
kHz/16kHz).To be mounte d on the ELCOT 16 cards.

CID8: 8-port Caller ID signal type FSK/FSK (with Visual Caller ID)/DTMF, To be mounted on the ELCOT16 cards.

Accessories and User-supplied Items

Accessories (included): Screws X 2

User-supplied (not included): none

Switch Settings (In case of install CID/PAY8 on ELCOT16 card)

Switch Type Usage and Status Definition

Port Setting DIP Set all DIP switch at “OFF” positions.

9

KX-TDA6181X

Fastening Amphenol Type Connector

An amphenol 57JE type connector is used on some of the optional sevice cards.

To connect an amphenol connector, use the spring latch or screw to fix the upper part and use Velcro

tape to fix the lower

part of the connector.

10

KX-TDA6181X

Using Analogue Trunk Card and Extension Card

Power Failure Connection connects a specific SLT and a trunk in the event of power failure. The following analogue trunk and
extension cards can be used for Power Failure Connections:

•

• •

• Analogue trunk card: ELCOT 16 (4 PFT ports)

•

• •

• Extension card: EMSLC16 (4 PFT ports), ESLC16 (4 PFT ports), DHLC8 (2 PFT port) and SLC8 (2 PFT port)

To 1 analogue trunk card, connect only 1 extension card.

Note:

•

• •

• Power Failure Connections must be made within the same shelf.

•

• •

• By programming the Hybrid IP-PBX, a trunk conversation established during power failure can be maintained even when the

power returns and the connection is switched back to the normal maintained even when the power returns and the
connection is switched back to the normal performed, the connection will be dropped when power returns.

Accessories and User-supplied Items

Accessories (included): none

User-supplied (not included): RJ11 connectors

11

KX-TDA6181X

RJ11 Connector Pin Assignments for Analogue Trunk Card

PFT Ports 1 and 2

No. Signal Name Function

1 R2 Ring port 2
2 R1 Ring port 1
3 T1 Tip port 1
4 T2 Tip port 2

PFT Ports 3 and 4

No. Signal Name Function

1 R4 Ring port 4
2 R3 Ring port 3
3 T3 Tip port 3
4 T4 Tip port 4

RJ11 Connector Pin Assignments for Extension Card

PFT Ports 1 and 2

No. Signal Name Function

1 T2 Tip port 2
2 T1 Tip port 1
3 R1 Ring port 1
4 R2 Ring port 2

PFT Ports 3 and 4 (for EMSLC16/ESLC16 card only)

No. Signal Name Function

1 T4 Tip port 4
2 T3 Tip port 3
3 R3 Ring port 3
4 R4 Ring port 4

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KX-TDA6181X

Installing Optional Service Cards

1. Insert the card along the guide rails.

2. Holding the card as follows, push the release lever in the direction of the arrow so that the card is made to engage with the
connector on the back board securely.

3. Turn the 2 screws clockwise to fix the card.

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KX-TDA6181X

6 BLOCK DIAGRAM

Tip

Ring

Tip

Ring

Tip

Ring

Tip

Ring

Tip

Ring

Tip

Ring

Tip

Ring

Tip

Surge

EMC

nLOOP[1]

IC1A

OP-AMP

Diag Relay

Port#1

Tip

Ring

IC3

ASIC

Diag-Tip, Diag-Ring

Transformer

Dial

DC Loop

&

CPC Det

Same as "Port#1".

Port#2

Same as "Port#1".

Port#3

Same as "Port#1".

Port#4

Same as "Port#1"

Port#5

Same as "Port#1"

Port#6

Port#7

Port#8

Same as "Port#1"

Same as "Port#1"

Rev/Bell
Detector

nREVDET[1]nBELDET[1]

nCPCDET[1]

nSHNT[1]

6

4

6

DIN
DOUT
DCLK
C_CS[3:0]

7
4

A[12:0]

8

D[7:0]

n

RD,nWR

nRES

T[8:1]

R[8:1]

PAY[8:1]

Caller ID
Pay Tone

Detect

(option1)

T[1]

R[1]

PAY

[1]

+3.3v

Tip

Ring

Tip

Ring

Tip

Ring

Tip

Ring

Tip

Ring

Tip

Ring

Tip

Ring

IC6

CODEC

IC7

CODEC

6

nRES

PORT#5-#8
PORT#9-#12(NO PFT)

PORT#13-#16(NO PFT)

Ring

DIAG[1]

PFT
Jack

#1,#2

PFT
Jack

#3,#4

6

6

6

6

6

6

4

4

FH
HWCLK(4M)
LDHW
LUHW

T[16:9]
R[16:9]

PAY

[16:9]

OPT1

Caller ID
Pay Tone

Detect

(option0)

OPT0

+3.3v

7
4

8

D

[7:0]

A[5:0]

TOE[7:0]
STD[7:0]

TOE [15:8]
STD[15:8]

4M

4M

+5V

+3.3V

Power
Supply

+15V

RESET

IC4

nRESET

JUMPER

MODE[5:0]

XTAL

16.384
MHz

PLLCLK

JUMPER

P1[7:0]

P22
P23

+3.3V

DRIVER

DRIVER

nRES

LED_RED

LED_GREEN

P20

P21

EC_CLK

nSYSTE_RST

EC_AD[15:0]

EC_BE[1:0]

EC_PAR

EC_FRAME

EC_TRDY
EC_STOP

EC_IDSEL

EC_PERR

EC_INT

CT_C8_A

CT_FRAME_A

CT_NETREF

CT_D[7:0]

nCS0

nCS1

IC401

LPR

A[22:0]
D[15:0]

nRD

nWR

XTAL/X401

12.288MHz

nCS[2:0]

BOARD

ID

3

nRESET

nIRQ1
nIRQ0

nBREQ
nBACK

NMI
nWDTOVF

IC402
Flash
ROM

IC403
RAM

nWR

nRD

nRD

nCS

nCS

A[19:0]

A[16:0]

D[15:0]

D[7:0]

nWR

nRESET

nBREQ
nBACK

nIRQ

nHALT

nCS0

nCS2

nCSI

nCS1

KX-TDA6181X ELCOT16 CARD BLOCK DIAGRAM

B
A
C
K
B
O
A
R
D

14

KX-TDA6181X

7 CIRCUIT OPERATIONS

7.1. CONTROL-SYSTEM CIRCUIT

7.1.1. CPU Peripherals

•

• •

• CPU (System clock: 12.288 MHz)......IC401

Data bus: 16bit, Address bus: 23bit

•

• •

• Flash ROM (512Kbyte)......IC402

Flash memory consists of two areas: boot space and adminis tration space.

Administration program can be rewritten through downloading.

•

• •

• SRAM (128Kbyte)......IC403

Used for the data buffer for CPU work area.

•

• •

• Reset

Resets of an ELCOT 16 card are roughly classified into the two kinds: ASIC reset and LPR reset.

After the release of the ASIC reset, the LPR reset is released by the soft reset from the side of the main card and the LPR
program is booted.

Type of reset Reset method Specification

ASIC reset ASIC reset is reset under the AND condition of reset signals (negative logic)

listed below.

Power-on reset Reset by reset IC
Hard reset from the main bus Reset by EC_RST signal
Soft reset from the main bus Released after the specified time

LPR reset Soft reset from the main bus Low active

Reset pulse width: 1.6 microseconds or more

•

• •

• LED Operation status indicating LED (Two colors)

OFF: Fault

Red ON: Fault (RESET included)

Green ON: Normal (Line not in use)

Green Flash (60/minute): Normal (Line in use)

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KX-TDA6181X

Orange: OUS (Because OUS needs to be controlled by EMPR, reset terminal and port control terminal are ORed to generate
OUS)

•

• •

• Instantaneous power interruption operation

When instantaneous power interruption is 300msec or less, reset operation is not carried out because the voltage is retained
by the capacitor in the power supply.

After HALT from EMPR is detected at the DC power down port, CPU goes into the sleep mode by executing the instruction of
SLEEP.

At the sleep mode, the CPU/Clock enter the halt state while the contents of the register, the internal RAM, and the I/O port is
maintained.

When the instantaneous power interruption is released, HALT is negated, and CPU is recovered to the normal mode by the
detection of IRQ0=L

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KX-TDA6181X

7.1.2. Time Slot Configuration

PCM data of an arbitrary stream, 0 - 15 (1 stream equals 128 time slots), on H.100 bus can be switched to an arbitrary local
highway (64 time slots) using a local TSW.

An example of time slot configuration of a local highway in ELCOT16 is shown below.

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KX-TDA6181X

7.1.3. IC3 (ASIC)

•

• •

• EC bus interface

16bit/8MHz two-way address data multiple x self-bus.

•

• •

• CT bus interface

Supports eight 8.192M Hz highways (128 time slots).

•

• •

• Local bus Interface

SH-1CPU by RENESAS Ltd. compatible bus with 8-bit data and 13bit address.

•

• •

• Local Highw ay Interface

Packs 2.048, 4.096, 8.192 MHz highway (Max.64 timeslot).

•

• •

• Local TSW

Timeslot switch between CT bus (1024ch) and local highway (64ch).

•

• •

• Local Gain Control

Gain control of the local highway up-down 64ch by 1dB/step randomly.

•

• •

• PT Interface

Selects the APT/DPT interfac e per port.

•

• •

• CODEC interface

A dedicated interfac e consisting of 4 Infineon PEB2466 chips for enabling the circuit controls.

•

• •

• GPIO Interface

A parallel interface that can be set in random interactively.

•

• •

• GPIO interface

Parallel interface that is arbitrarily programmable bidirectionally.

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KX-TDA6181X

7.2. DESCRIPTION OF FUNCTIONS AND CIRCUITS

7.2.1. Dial Pulse Signal Transmission

Transmits 10pps/20pps dial pulse by a open/close action between Tip and Ring with Photo MOS relay.

The make width, break width and inter digital width for 10pps/20pps can be set respectively.

When making, 37pin (DIAL [0]) of IC6 becomes Low level, and PL2 turns ON. When breaking, 37pin (DIAL [0]) of IC6 becom es
High level, and PL2 turns OFF.

It provides the SHUNT control function for the stabilization of line power depending on the destination. Turning ON PC5 when
transmitting pulse reduces the impedance at making, and stabilizes the line power.

7.2.2. Circuit For Line Acquisition

Making 37pin (DIAL[0]) of IC6 Low level, the photo MOS relay (PL2) turns ON and the line is acquired.

It is used in common as Dial Pulse transmitting circuit.

DC Loop Path:

•

• •

• Ring→L3→L2→RL1→J5→D2→PL2→ Q6(C-E)→R5→R80→D2→RL1→J3→L1→L4→J7→Tip

•

• •

• Tip→J7→L4→L1→J3→RL1→D2→PL2→ Q6(C-E)→R5→R80→D2→J5→RL1→L2→L3→Ring

7.2.3. DTMF Signal Transmission

This transmits the DTMF signal on the highway timeslot. The different DTMF signals can be transmitted to the optional ports at the
same time.

They are transmitted to the line through CODEC.

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KX-TDA6181X

7.2.4. Bell Signal Detection

During on-hook, transmitting the bell signal to the AC loop in the CR series circuits (C2 and R2) detects the current by Photo
Coupler (PC1,2), and it determines the presence of a bell signal. Software performs the operation for recognition and determination
of a pattern of bell signals.

Bell Loop Path:

•

• •

• Ring→L3→L2→RL1→R50→PC1(1-2)→C2→R2→J9→RL1→J3→L1→L4→J7→Tip

In this path, PC1 4-pin converts from High to Low, and a bell signal is detected.

•

• •

• Tip→J7→L4→L1→J3→RL1→J9→R2→C2→PC2(1-2)→R50→ RL1→L2→L3→Ring

In this path, PC2 4-pin converts from High to Low, and a bell signal is detected.

7.2.5. DTMF Signal Detection

This is provided on the CALLER ID detectio n card (CID8) and CALLER ID/PAYTONE detection card (CID/PAY8) of the option
cards.

7.2.6. Polarity Reversal Detection

Configured by the photo couplers (PC1,PC2) which enables current detection in either the Tip → Ring or Ring → Tip directions.
(PC2 is used in common as the bell detection photo coupler). Using Software, it stores the current direction (the detected photo
coupler) of the connected trunk and adjusts the direction of the current flow detectio n. (the detected photo coupler changes).

When the current flows in the direction of Ring to Tip, PC1 4-pin is Low and PC2 4-pin is High.

•

• •

• Ring→L3→L2→RL1→R50→PC1(1-2)→J5→D2→PL2→Q6(C-E)→R5→R80→D2→ RL1→J3→L1→L4→J7→Tip

When the current direction (polarity) is reversed from Tip to Ring, PC1 4-pin turns to High and PC2 4-pin turns to Low. It recognizes
the action by changing of the current direction (the detected photo coupler changes).

•

• •

• Tip→J7→L4→L1→J3→RL1→D2→PL2→ Q6(C-E)→R5→R80→D2→J5→PC2(1-2)→R50→RL1→L2→L3→Ring

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KX-TDA6181X

7.2.7. 2W-4W Conversion

This converts 4W-voice signal inside PBX and 2W-voice signal on SLT or Trunk. It is configured by Op-Amp and BN (Balance
Network) in CODEC. It affects the return loss of the voice and the frequency characteristic, and is determined by setting the best
value of Infineon CODEC and a software register.

7.2.8. Interface

•

• •

• CODEC Control...IC6, IC7, IC9, IC10

This uses PEB2466 by Infineo n. CODEC interface DCLK, CS, DOUT and DIN configure the analog characteristic such as BN,
frequency characteristic, level, lateral constant. Also, the built-in I/O port is used as CPC detection, DIAL control, BELL
detection, Reverse detection, DIAL Shunt control and DIAG relay control.

•

• •

• A/D, D/A Conversion

This converts 4Wire analog signal and G.711 PCM (µ/A).

7.2.9. Surge Protection

A gas arrester (SA1) with the discharge voltage 230V is mounted between T and SFG, R and SFG. And a discharge tube (SA3)
with the discharge voltage 1KV is mounted between SFG and FG. Furthermore, ZNR (ZNR1) with the discharge voltage 82V is
mounted on the PBX side of the photo MOS relay for each line.

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KX-TDA6181X

7.2.10. Power Failure Port

At the time of the power failure, for enabling a direct call to the extension phone, 4lines out of 16lines can be connected to the SLT
port, which provides a switching relay for power failure on the extension card, by a cable. It connects CN3, CN4 with the connector
for power failure on the extension card.

7.2.11. Self-Diagnostic Relay

Self-diagnostic relays are mounted on each port. It enters normal mode at DIAG=L, and enters self-diagnostic mode at DIAG=H.
At the self-diagnostic mode, Tip-Ring connects to Tip-Ring being in the pairing extension card via the backboard. That allows self­diagnostic feature to be perform ed.

The items of self-diagnosis for ELCOT16 circuits are BELL signal detection, line addition, dial pulse transm ission and DTMF
transmission.

7.2.12. Option Cards

The following Option cards can be mounted :

1) 2 x Caller ID Detection cards (CID8).

2) 2 x Caller ID / Paytone Detection cards (CID/PAY8).

7.3. POWER SUPPLY CIRCUIT

•

• •

• DC/DC conversion circuit

The circuit which generates output +3.3V, +5V with input +15V. It is configured with the circuit that reduces the voltage from
+15V to +3.3V by IC1, Q1 and L31 switching power supply, and with the circuit that reduces the voltage from +15V to +5V by
IC2, Q2 and L32 switching power supply.

There are some protection lines. First is IP2 for +3.3V short protection, second is IP3 for +5V short protection, third is the
overvoltage protection which detects +3.3V/+5V excess voltage rise and makes the FET(Q6) turn ON which blows IP1.

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KX-TDA6181X