Panasonic KXTG5776S User manual

© 2006 Panasonic Communications Co., Ltd. All
rights reserved. Unauthorized copying and distribu-
tion is a violation of law.
ORDER NO. KM40602997CE
F12
Telephone Equipment
KX-TG5776S
KX-TG5777S
KX-TGA571S
5.8 GHz Expandable Digital Cordless
Answering System
5.8 GHz Expandable Digital Cordless
Answering System with Two Handsets
Silver Version
(for U.S.A.)

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KX-TG5776S/KX-TG5777S/KX-TGA571S

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KX-TG5776S/KX-TG5777S/KX-TGA571S
TABLE OF CONTENTS
PAGE PAGE
1 Safety Precaution ------------------------------------------------ 4
1.1. For Service Technicians --------------------------------- 4
2 Warning -------------------------------------------------------------- 4
2.1. Battery Caution--------------------------------------------- 4
2.2. About Lead Free Solder (Pbf: Pb free)--------------- 4
3 Specifications ----------------------------------------------------- 6
4 Technical Descriptions ----------------------------------------- 7
4.1. FHSS Description ----------------------------------------- 7
4.2. Explanation of Link Data Communication ----------10
4.3. Block Diagram (Base Unit_Main)---------------------11
4.4. Block Diagram (Base Unit_RF Part) -----------------12
4.5. Circuit Operation (Base Unit) --------------------------13
4.6. Block Diagram (Handset_Main)-----------------------22
4.7. Block Diagram (Handset_RF Part)-------------------23
4.8. Circuit Operation (Handset)----------------------------24
4.9. Circuit Operation (RF Part)-----------------------------29
4.10. Circuit Operation (Charger Unit) ----------------------34
4.11. Signal Route -----------------------------------------------35
5 Location of Controls and Components ------------------37
5.1. Controls -----------------------------------------------------37
5.2. Displays -----------------------------------------------------38
6 Installation Instructions ---------------------------------------40
6.1. Setting Up the Base Unit -------------------------------40
6.2. Setting Up the Handset ---------------------------------40
6.3. Battery Installation/Replacement ---------------------41
6.4. Battery Charge --------------------------------------------41
6.5. Expanding Your Phone System-----------------------43
7 Operation Instructions-----------------------------------------44
7.1. Symbols Used in These Operating
Instructions -------------------------------------------------44
7.2. Programmable Settings ---------------------------------45
7.3. Error Messages -------------------------------------------49
7.4. Troubleshooting-------------------------------------------50
8 Test Mode ----------------------------------------------------------54
8.1. Adjustment and Test Mode Flow Chart -------------54
9 Service Mode -----------------------------------------------------63
9.1. How to Clear User Setting------------------------------63
10 Troubleshooting Guide ----------------------------------------64
10.1. Troubleshooting Flowchart -----------------------------64
10.2. How to Replace the Flat Package IC----------------77
10.3. How to Replace the LLP (Leadless Leadframe
Package) IC------------------------------------------------79
11 Disassembly and Assembly Instructions ---------------81
11.1. Disassembly Instructions -------------------------------81
11.2. Fix the LCD and the Receiver Guide to the
Main P.C. Board (Handset)-----------------------------84
12 Measurements and Adjustments---------------------------85
12.1. Things to Do after Replacing IC ----------------------85
12.2. Base Unit Reference Drawing-------------------------86
12.3. Handset Reference Drawing---------------------------87
12.4. Frequency Table ------------------------------------------88
13 Schematic Diagram ---------------------------------------------90
13.1. For Schematic Diagram---------------------------------90
13.2. Schematic Diagram (Base Unit_Main) --------------92
13.3. Schematic Diagram (Base Unit_RF Part) ----------94
13.4. Schematic Diagram (Base Unit_Operation) -------96
13.5. Schematic Diagram (Handset_Main) ----------------98
13.6. Schematic Diagram (Handset_RF Part) ---------- 100
13.7. Schematic Diagram (Charger Unit)---------------- 102
14 Printed Circuit Board ---------------------------------------- 103
14.1. Circuit Board (Base Unit_Main) -------------------- 103
14.2. Circuit Board (Base Unit_RF Part)----------------- 105
14.3. Circuit Board (Base Unit_Operation)-------------- 107
14.4. Circuit Board (Handset_Main) ---------------------- 109
14.5. Circuit Board (Handset_RF Part) -------------------111
14.6. Circuit Board (Charger Unit)--------------------------112
15 Appendix Information of Schematic Diagram --------113
15.1. CPU Data (Base Unit) ---------------------------------113
15.2. CPU Data (Handset) -----------------------------------114
15.3. Explanation of IC Terminals (RF Part) -------------115
15.4. Terminal Guide of the ICs, Transistors and
Diodes -----------------------------------------------------118
16 Exploded View and Replacement Parts List ----------119
16.1. Cabinet and Electrical Parts (Base Unit) ----------119
16.2. Cabinet and Electrical Parts (Handset)----------- 120
16.3. Cabinet and Electrical Parts (Charger Unit) ----- 121
16.4. Accessories and Packing Materials --------------- 122
16.5. Replacement Parts List------------------------------- 124

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KX-TG5776S/KX-TG5777S/KX-TGA571S
1 Safety Precautions
1.1. For Service Technicians
ICs and LSIs are vulnerable to static electricity.
When repairing, the following precautions will help prevent recurring malfunctions.
1. Cover plastic parts boxes with aluminum foil.
2. Ground the soldering irons.
3. Use a conductive mat on worktable.
4. Do not grasp IC or LSI pins with bare fingers.
2Warning
2.1. Battery Caution
1. Danger of explosion if battery is incorrectly replaced.
2. Replace only with the same or equivalent type recommended by the manufacturer.
3. Dispose of used batteries according to the manufacturer's Instructions.
2.2. About Lead Free Solder (Pbf: Pb free)
Note:
In the information below, Pb, the symbol for lead in the periodic table of elements, will refer to standard solder or solder that con-
tains lead.
We will use PbF solder when discussing the lead free solder used in our manufacturing 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.
Caution
• PbF solder has a melting point that is 50°F ~ 70°F (30°C ~ 40°C) higher than Pb solder. Please use a soldering iron with temper-
ature control and adjust it to 700°F ± 20°F (370°C ± 10°C).
• Exercise care while using higher temperature soldering irons.:
Do not heat the PCB for too long time in order to prevent solder splash or damage to the PCB.
• PbF solder will tend to splash if it is heated much higher than its melting point, approximately 1100°F (600°C).
• When applying PbF solder to double layered boards, please check the component side for excess which may flow onto the
opposite side (See the figure below).

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KX-TG5776S/KX-TG5777S/KX-TGA571S
2.2.1. 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 manufac-
turer’s specific instructions for the melting points of their products and any precautions for using their product with other materi-
als.
The following lead free (PbF) solder wire sizes are recommended for service of this product: 0.3 mm, 0.6 mm and 1.0 mm.
2.2.2. How to Recognize that Pb Free Solder is Used
(Example: Handset P.C.B.)
(Component View)
Note:
The location of the “PbF” mark is subject to change without notice.
IC201
IC241
PbF
IC801
IC701
IC851
IC246
Marked

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KX-TG5776S/KX-TG5777S/KX-TGA571S
3 Specifications

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KX-TG5776S/KX-TG5777S/KX-TGA571S
4 Technical Descriptions
4.1. FHSS Description
4.1.1. Frequency
The frequency range of 5.76 GHz-5.84 GHz is used. Transmitting and receiving channel between Base Unit and Handset is same
frequency. Refer to Frequency Table (P.88).
4.1.2. FHSS (Frequency Hopping Spread Spectrum)
This telephone is using an IC chip which has similar specification to WDCT (World Digital Cordless Telephone) and is the tele-
phone system that can use multiple portable unit simultaneously. The explanation of this system is mentioned below. This sys-
tem uses a Time Division Multiple Access/Time Division Duplex (TDMA/TDD) scheme:
transmitting and receiving frequencies of the Base Unit and Handset are shared in the same frequency. The construction of RX/
TX frequency data is shown below. It consists of 4 slots from the Base Unit to the Handset, and 4 slots from the Handset to the
Base Unit, total 8 slots in 10 ms. By this slot system, simultaneous air link and communication between 4 Handsets and the
Base Unit can be realized. One communication between Handset and the Base Unit is done by one slot from the Base Unit to
Handset, and another slot from Handset to the Base Unit.
DSS makes spectrum spread by multiplying carrier signal by PN code. The purpose to make spectrum spread is to reduce
power density per time and per band. On the other hand, FHSS makes spectrum spread by changing channel every 10 ms
according to Hopping table. Also the purpose to make spectrum spread is to reduce power density per time and per band.

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KX-TG5776S/KX-TG5777S/KX-TGA571S
4.1.2.1. TDD Frame Format
Sync Field (72 bit): Preamble 56 bit + SyncWord 16 bit
Base Unit (Handset) adjusts the timing of reception so that reception of Base Unit (Handset) can correspond to transmission of
Handset (Base Unit).
It is necessary for sync-field that Handset gets synchronization.
A - field (64 bit): Each kinds of DATA: ch data, line condition, etc.
B - field (320 bit + 80 bit): Sound data + parity
Z - field (4 bit): Parity Check
4.1.2.2. TDMA system
This system is the cycles of 10 ms, and has four duplex paths,
so it is possible to perform four duplex communications simultaneously.
(Up to eight Handsets can be registered)
In 1 slot 1.25 ms, the 10 ms of voice data is transmitted.
Each slot makes every frame frequency hop. (100 hops/sec.)
Although each slot (UpLink3 and UpLink4) uses different frequency, UpLink3 and DownLink3 use the same frequency.
•2 - Handsets Link
Traffic Bearer
A link is established between Base Unit and Handset.
The state where duplex communication is performed.
The hopping pattern of a 3000 hops (30 seconds) cycle.
Dummy Bearer
The Base Unit sends Dummy-data to the all stand-by state Handsets.
The Handsets receive that data for keeping synchronization and monitoring request from the Base Unit.
Dummy Bearer doesn't contain B-field (sound) data.

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KX-TG5776S/KX-TG5777S/KX-TGA571S
4.1.3. Signal Flowchart in the Whole System
Reception
CN101 of the Base Unit is connected to the TEL line, and signal is enter through the bridge diode D101. While talking, the relay
(Q141) is turned ON and amplified at the Q171, then led to DSP (IC501). The DSP encodes ADPCM and TDD/TDMA with
FHSS to TXMOD. The TXMOD signal is enter to IC701 of RF PART, and modulated to 2.4 GHz. The 2.4 GHz signal is up-
converted to 5.8 GHz RF signal by IC801. The RF signal is amplified by the power amplifier (IC851) and fed to Antennas.
As for the Handset, RF signal from the antenna is amplified by LNA (IC851). The amplified signal is down-converted to 2.4 GHz
signal by IC801 and led to IC701. The 2.4 GHz is down-converted to IF signal in IC701. The IF signal passing through internal
filter is demodulated into RXDATA, then enter to DSP (IC201). The DSP performs TDD/TDMA and ADPCM decoding to convert
the RXDATA into the voice signal, then it is output to the speaker.
Transmission
The voice signal entering from the Handset microphone is led to DSP (IC201). The DSP encodes ADPCM and TDD/TDMA with
FHSS to TXMOD. The TXMOD signal is enter to IC701 of RF PART, and modulated to 2.4 GHz. The 2.4 GHz signal is up-
converted to 5.8 GHz RF signal by IC801. The RF signal is amplified by the power amplifier (IC851) and fed to Antenna.
As for the Base Unit, RF signal from the Antennas is amplified by LNA (IC851). The amplified signal is down-converted to 2.4
GHz signal by IC801 and led to IC701. The 2.4 GHz is down-converted to IF signal in IC701. The IF signal passing through
internal filter is demodulated into RXDATA, then enter to DSP (IC501). The DSP performs TDD/TDMA and ADPCM decoding to
convert the RXDATA into the voice signal. The voice signal is amplified at the TX amplifier (Q161), then output to the TEL line
CN101 through the relay (Q141) and bridge (D101).

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KX-TG5776S/KX-TG5777S/KX-TGA571S
4.2. Explanation of Link Data Communication
4.2.1. Calling
4.2.2. To Terminate Communication
4.2.3. Ringing

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KX-TG5776S/KX-TG5777S/KX-TGA571S
4.3. Block Diagram (Base Unit_Main)
KX-TG5776/5777 BLOCK DIAGRAM (Base Unit_Main)
D101
CHARGE_CONTACT
+ -
MIC
SP
X501
13.824MHz
ANT1ANT0
CN101
TEL JACK
Tip Ring
CN301
DC JACK
DC+ DC-
RLY
SIDE TONE CIRCUIT
Q161 R151,R152
Q141
BELL DETECT
RLY
DCIN2
BELL
CHARGE DETECT
Q111
LIN
LOUT
Q361,Q362
RF_PART
HSMIN
HSMIP
IC501
DSP
CHG
4.0V CONVERTOR
SPOUTP
SPOUTN
MIN
INUSE DETECT1
RECEIVE AMP
DCIN1
IC331
RESET
POWER_DOWN
VCCIN
VCC
VCCA
VCCPA
CHARGE CURRENT
CHG_CTL
INT_1
V_RF
INT_1 5
VCC
IC601
FLASH MEMORY
LCD
KEYS
Operational P.C.Board
IC300
, Q300
R131,R132
Q171
R371 ~ R373
RSSI SHCTRL RADIO_EN TX_EN RX_EN LO_EN SYN_DATA SYN_CLK
OSC_IN
SYN_LE2 TXDATA
V_RF(VPA)
Q535
SI,SO,CS,
COM1 ,COM2
SEG3 12
OSC_IN
KEY1 6
KEYA F
RXDATA
MIP
SYN_LE1 SYN_OUT RX_GAIN RF_RESET
3.3V
REGULATOR with RESET
CLK,RST
ANT0 PA_CONT
AC_DOWN
Q340
AC DOWN
INUSE DETECT2
ANSWER_LED
INUSE_LED
MSG_LED
SP_PHONE_LED

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KX-TG5776S/KX-TG5777S/KX-TGA571S
4.4. Block Diagram (Base Unit_RF Part)
ANT_1 ANT_0
IC701
XIN
TXEN
TC_CTRL
RSTN
RXEN
IC761
2.5V
REGULATOR
3.0V
REGULATOR
IC841
Power Supply Circuit
-
Frac-N
PLL
2MHz
FM det. Slicer
Serial Interface
VCC
2.4GHz Mod/Demod Circuit
2.4GHz 2.4GHz
FL811
FL891 FL881
IC851
5.8GHz Power Amp., 5.8GHz LNA and Antenna Switch Circuit
V_PA V_RF
RADIO_EN SYN_LE2 SYN_CLK SYN_DATA SYN_LE1 OSC_IN TX_EN SYN_OUT TX_DATA RX_DATA RSSI SHCTRL RF_RESET RX_EN RX_GAIN
DSP
PLL
Serial Interface
5.8GHz Converter Circuit
IC801 3.4GHz
5.8GHz
PA_CONT
VCC
TXEN
REFIN
ANT0
RXEN
RXGAIN
5.8GHz
FL821
KX-TG5776/5777 BLOCK DIAGRAM (Base Unit_RF Part)

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KX-TG5776S/KX-TG5777S/KX-TGA571S
4.5. Circuit Operation (Base Unit)
General Description:
(DSP, Flash Memory) is a digital speech/signal processing system that implements all the functions of speech compression,
record and playback, and memory management required in a digital telephone answering machine.
The DSP system is fully controlled by a host processor DSP. The host processor provides activation and control of all that
functions as follows.
4.5.1. DSP (Digital Speech/Signal Processing: IC501)
•Voice Message Recording/Play back
The DSP system use a proprietary speech compression technique to record and store voice message in Flash Memory.
An error correction algorithm is used to enable playback of these messages from the Flash Memory.
•DTMF Detection/Generator
The DTMF detection is implemented by the DSP system in software. The DTMF detection is performed during Record, Play
back, and Line Monitoring modes of operation.
When the DTMF data from the Handset is received, the DTMF signal is output.
•Synthesized Voice (Pre-recorded message)
The DSP implements synthesized Voice, utilizing the built in speech detector and a Flash Memory, which stored the vocabulary.
•Caller ID and Call Waiting CID demodulation
The DSP implements monitor and demodulate the FSK signals that provide CID information from the Central Office.
•Analog Switching
The voice signal from telephone line is transmitted to the speaker or the voice signal from speakerphone microphone is
transmitted to the Telephone line, etc. They are determined by the signal path route operation of voice signal.
•Block Interface Circuit
RF part, LED, Key scan, Speaker, Microphone, Telephone line, LCD.
4.5.2. Flash Memory (IC601)
Following information data is stored.
•Voice signal
ex: Pre-recorded Greeting message, Incoming message, Talking Caller ID announcement
•Settings
ex: message numbers, ID code, Flash Time, Tone/Pulse

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KX-TG5776S/KX-TG5777S/KX-TGA571S
4.5.3. Power Supply Circuit
Function:
The power supply voltage from AC adaptor is converted to the desired voltage of each block.
Circuit Operation:
• Q300 and IC300: 4.0 V DCDC Converter
• IC331: 3.3 V Regulator

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KX-TG5776S/KX-TG5777S/KX-TGA571S
4.5.3.1. Charge Circuit
The voltage from the AC adaptor is supplied to the charge circuits. Main charge (130 ~ 220 mA at the Battery) of maximum
7-hours is started soon after the Handset is placed on the Base Unit. Then it changes to Trickle charge to prevent from
overcharging.
Q361 and Q362 detect the ON-HOOK state (Handset is placed on Base Unit).

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KX-TG5776S/KX-TG5777S/KX-TGA571S
4.5.4. Reset Circuit
Function:
This circuit is used to initialize the microcomputer when it incorporates an AC adaptor.
Circuit Operation:
When the AC Adaptor is inserted into the unit, then the voltage is shifted by IC331 and power is supplied to the DSP.
The set starts to operate when VCC goes up to 3.0 V or more in the circuit voltage diagram.
Note:
(*1) The initializing time of the DSP chip is 28 ms under normal conditions.

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KX-TG5776S/KX-TG5777S/KX-TGA571S
4.5.5. Telephone Line Interface
Telephone Line Interface Circuit:
Function
• Bell signal detection
• ON/OFF hook and pulse dial circuit
• Side tone circuit
Bell signal detection and OFF HOOK circuit:
In the idle mode, Q141 is open to cut the DC loop current and decrease the ring load. When ring voltage appears at the Tip (T)
and Ring (R) leads (When the telephone rings), the AC ring voltage is transferred as follows:
T →L101 →R111 →C111 →Q111 →DSP pin 3 [BELL]
When the CPU (DSP) detects a ring signal, Q141 turns on, thus providing an off-hook condition (active DC current flow through
the circuit). Following signal flow is the DC current flow.
T →L101 →D101 →Q141 →Q161 →R163 →D101 →L102 →P101 →R
ON HOOK Circuit:
Q141 is open, Q141 is connected as to cut the DC loop current and to cut the voice signal. The unit is consequently in an
on-hook condition.
Pulse Dial Circuit:
Pin 59 of DSP turns Q141 ON/OFF to make the pulse dialing.
Side Tone Circuit:
Basically this circuit prevents the TX signal from feeding back to RX signal. As for this unit, TX signal feed back from Q161 is
canceled by the canceller circuit of DSP.

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KX-TG5776S/KX-TG5777S/KX-TGA571S
4.5.6. Auto Disconnect circuit
Function:
This circuit is used to detect the fact that another telephone connected to the same line is OFF-HOOK while the unit is in a
receiving status or OGM transmitting status.
Circuit Operation:
The voltage of pin 90 of IC501 is monitored. If a parallel-connected telephone is put into OFF-HOOK status, the presence/
absence of a parallel connection is determined when the voltage changes by 0.2 V or more. When the set detects the parallel-
connected telephone is OFF-HOOK status, the line is disconnected.
You can enable or disable the Auto Disconnect function.
See Check Record (P.66)

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KX-TG5776S/KX-TG5777S/KX-TGA571S
4.5.7. Parallel Connection Detect Circuit
Function:
In order to disable call waiting and stutter tone functions when using telephones connected in parallel, it is necessary to have a
circuit that judges whether a telephone connected in parallel is in use or not. This circuit determines whether the telephone
connected in parallel is on hook or off hook by detecting changes in the T/R voltage.
Circuit Operation:
Parallel connection detection when on hook:
When on hook, the voltage is monitored at pin 86 of IC501. There is no parallel connection if the voltage is
1.65 V or higher, while a parallel connection is deemed to exist if the voltage is lower.
Parallel connection detection when off hook:
When off hook, the voltage is monitored at pin 90 of IC501; the presence/absence of a parallel connection is determined when
the voltage changes by 0.2 V or more.

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KX-TG5776S/KX-TG5777S/KX-TGA571S
4.5.8. Calling Line Identification (Caller ID)/Call Waiting Caller ID
Function:
Caller ID
The caller ID is a chargeable ID which the user of a telephone circuit obtains by entering a contract with the telephone company
to utilize a caller ID service. For this reason, the operation of this circuit assumes that a caller ID service contract has been
entered for the circuit being used. The data for the caller ID from the telephone exchange is sent during the interval between the
first and second rings of the bell signal. The data from the telephone exchange is a modem signal which is modulated in an FSK
(Frequency Shift Keying) * format. Data “1” is a 1200 Hz sine wave, and data.... a 2200 Hz sine wave. There are two types of the
message format which can be received: i.e. the single message format and plural message format. The plural message format
allows to transmit the name and data code information in addition to the time and telephone number data.
*: Also the telephone exchange service provides other formats.