LG CX8700, CX8700B, CX8700BWA Service Manual

Features of CX8700

1. Wave Type

CELLULAR : G7W

•

• PCS : G7W

2. Frequency Scope

Transmit Frequency (MHz)

Receive Frequency (MHz)

CELLULAR

824.82 ~ 848.19 1850~1910 869.82~893.19 1930~1990 1575.42

3. Rated Output Power :

PCS = 0.20W

4. Output Conversion Method :

5. Voltage and Current Value of Termination Part Amplifier (Catalogue included)

MODE Part Name Voltage Current Power

CELLULAR AWT6310R 4.2V 600mA 0.20W

PCS AWT6310R 4.2V 600mA 0.20W

PCS

CELLULAR = 0.20W

This is possible by correcting the key board channel.

CELLULAR

PCS

6. Functions of Major Semi-Conductors

Classification Function

MSM6550 Terminal operation control and digital signal processing

GPS

Memory MCP

(HYI0UGG0MF1P-6SS0E)

RFR6500 Converts Rx RF signal to baseband signal
RFT6150 Converts baseband signal to Tx RF signal

7. Frequency Stability

• CELLULAR : ±0.5PPM
PCS : ±0.1PPM

•

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Flash Memory (1Mbit) + SDRAM (512Mbit)
Storing of terminal operation program

CX8700

CDMA Mobile Subscriber Unit

CX8700

SERVICE MANUAL

TRI BAND CDMA

[PCS/Cellular/GPS]

CDMA MOBILE PHONE

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CX8700

Table of Contents

General Introduction

........................................................................................................................................ 4

CHAPTER 1. System Introduction

1. System Introduction......................................................................................................................5

2. Features and Advantages of CDMA Mobile Phone .................................................................6

3. Specification...................................................................................................................................9

4. Installation ..................................................................................................................... 14

CHPATER 2. NAM Input Method

1. NAM Program Method and Telephone Number Inputting Method .................................16

CHAPTER 3. Circuit Description

1. RF Transmit/Receive Part..........................................................................................................26

2. Digital/Voice Processing Part.....................................................................................................33

CHAPTER 4. Trouble Shooting……………………………………………….…………………….37

CHAPTER 5. Safety……………………………………………………………….……………..…..88

CHAPTER 6. Glossary………………………………………………………….………………..…..91

APPENDIX……………………………………………………………………………………….….103

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CX8700

General Introduction

The CX8700 phone has been designed to operate on the latest digital mobile communication technology, Code
Division Multiple Access (CDMA). This CDMA digital technology has greatly enhanced voice clarity and can
provide a variety of advanced features. Currently, CDMA mobile communication technology has been
commercially used in Cellular and Personal Communication Service (PCS). The difference between them is the
operating frequency spectrum. Cellular uses 800MHz and PCS uses 1.9GHz. The CX8700 support GPS Mode,
we usually call it tri-band phone. Also, CX8700 works on Advanced Mobile Phone Service (S-GPS). We call it
dual-mode phone. If one of the Cellular, PCS base stations is located nearby, Call fail rate of triple-mode phone
is less than dual-mode phone or single-mode phone.
The CDMA technology adopts DSSS (Direct Sequence Spread Spectrum). This feature of DSSS enables the
phone to keep communication from being crossed and to use one frequency channel by multiple users in the
same specific area, resulting that it increases the capacity 10 times more compared with that in the analog mode
currently used. Soft/Softer Handoff, Hard Handoff, and Dynamic RF power Control technologies are combined
into this phone to reduce the call being interrupted in a middle of talking over the phone.
Cellular and PCS CDMA network consists of MSO (Mobile Switching Office), BSC (Base Station Controller),
BTS (Base station Transmission System), and MS (Mobile Station). The following table lists some major
CDMA Standards.

CDMA Standard Designator Description

Basic air interface TIA/EIA/IS-95-A/B/C

ANSI J-STD-008

Network TIA/EIA/IS-634

TIA/EIA/IS/651

TIA/EIA/IS-41-C

TIA/EIA/IS-124

Service TIA/EIA/IS-96-B

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TIA/EIA/IS-99
TIA/EIA/IS-637
TIA/EIA/IS-657

Protocol between MS and BTS for Cellular & AMPS

Protocol between MS and BTS for PCS

MAS-BS

PCSC-RS

Intersystem operations

Nom-signaling data comm.

Speech CODEC

Assign data and fax

Short message service

Packet data

Performance TIA/EIA/IS-97

TIA/EIA/IS-98

ANSI J-STD-018
ANSI J-STD-019

TIA/EIA/IS-125

* TSB –74: Protocol between an IS-95A system and ANSI J-STD-008

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Cellular base station

Cellular mobile station

PCS personal station

PCS base station

Speech CODEC

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CX8700

Chapter1. System Introduction

1.1 CDMA Abstract

The CDMA mobile communication system has a channel hand-off function that is used for collecting the
information on the locations and movements of mobile telephones from the cell site by automatically controlling
several cell site through the setup of data transmission routes, and then enabling one switching system to carry
out the automatic remote adjustment. This is to maintain continuously the call state through the automatic
location confirmation and automatic radio channel conversion when the busy subscriber moves from the service
area of one cell site to that of another by using automatic location confirmation and automatic radio channel
conversion functions. The call state can be maintained continuously by the information exchange between
switching systems when the busy subscriber moves from one Cellular system area to the other Cellular system
area.

In the Cellular system, the cell site is a small-sized low output type and utilizes a frequency allocation system
that considers mutual interference, in an effort to enable the re-use of corresponding frequency from a cell site
separated more than a certain distance.

Unlike the time division multiple access (TDMA) or frequency division multiple access (FDMA) used in the
band limited environment, the Code Division Multiple Access (CDMA) system which is one of digital Cellular
systems is a multi-access technology under the interference limited environment. It can process more number of
subscribers compared to other systems (TDMA system has the processing capacity three times greater than the
existing FDMA system whereas CDMA system, about 12~15 times of that of the existing system).

CDMA system can be explained as follows; TDMA or CDMA can be used to enable each person to talk
alternately or provide a separate room for each person when two persons desire to talk with each other at the
same time, whereas FDMA can be used to enable one person to talk in soprano, whereas the other in bass (one
of the two talkers can carry out synchronization for hearing in case there is a bandpass filter function in the area
of the hearer). Another available method is to make two persons to sing in different languages at the same time,
space, and frequency when wishing to let the audience hear the singing without being confused. This is the
characteristic of CDMA.

On the other hand, when employing the CDMA technology, each signal has a different pseudo-random binary
sequence used to spread the spectrum of carrier. A great number of CDMA signals share the same frequency
spectrum. In the perspective of frequency area or time area, several CDMA signals are overlapped. Among these
types of signals, only desired signal energy is selected and received through the use of pre-determined binary
sequence; desired signals can be separated, and then received with the correlator used for recovering the
spectrum into its original state. At this time, the spectrums of other signals that have different codes are not
recovered into its original state, and appears as the self-interference of the system.

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CX8700

2. Features and Advantages of CDMA Mobile Phone

2.1 Various Types of Diversities

When employing the narrow band modulation (30kHz band) that is the same as the analog FM modulation
system used in the existing Cellular system, the multi-paths of radio waves create a serious fading. However, in
the CDMA broadband modulation (1.25MHz band), three types of diversities (time, frequency, and space) are
used to reduce serious fading problems generated from radio channels in order to obtain hig h-quality calls.
Time diversity can be obtained through the use of code interleaving and error correction code whereas frequency
diversity can be obtained by spreading signal energy to wider frequency band. The fading related to normal
frequency can affect the normal 200~300KHz among signal bands and accordingly, serious effect can be
avoided. Moreover, space diversity (also called path diversity) can be realized with the following three types of
methods.
First, it can be obtained by the duplication of cell site receive antenna. Second, it can be obtained through the
use of multi-signal processing device that receives a transmit signal having each different transmission delay
time and then, combines them. Third, it can be obtained through the multiple cell site connection (Soft Handoff)
that connects the mobile station with more than two cell sites at the same time.

2.2 Power Control

The CDMA system utilizes the forward (from a base station to mobile stations) and backward (from the mobile
station to the base station) power control in ord er to in crease the call p ro cessing capacity an d ob tain h igh -q uality
calls. In case the originating signals of mobile stations are received by the cell site in the minimum call quality
level (signal to interference) through the use of transmit power control on all the mobile stations, the system
capacity can be maximized.If the signal power of mobile station is received too strong, the performance of that
mobile station is improved. However, because of this, the interference on other mobile stations using the same
channel is increased and accordingly, the call quality of other subscribers is reduced unless the maximum
accommodation capacity is reduced.
In the CDMA system, forward power control, backward open loop power control, and closed loop power control
methods are used. The forward power control is carried out in the cell site to reduce the transmit power on
mobile stations less affected by the multi-path fading and shadow phenomenon and the interference of other cell
sites when the mobile station is not engaged in the call or is relatively nearer to the corresponding cell site. This
is also used to provide additional power to mobile stations having high call error rates, located in bad reception
areas or far away from the cell site.
The backward open loop power control is carried out in a corresponding mobile station; the mobile station
measures power received from the cell site and then, reversely increases/decreases transmit power in order to
compensate channel changes caused by the forward link path loss and terrain characteristics in relation to the
mobile station in the cell site. By doing so, all the mobile transmit signals received by the base station have same
strength.
Moreover, the backward closed loop power control used by the mobile station is performed to control power
using the commands issued out by the cell site. The cell site receives the signal of each corresponding mobile
station and compares this with the pre-set threshold value and then, issues out power increase/decrease
commands to the corresponding mobile station every 1.25msec (800 times per second). By doing so, the gain
tolerance and the different radio propagation loss on the forward/backward link are complemented.

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CX8700

2.3 Voice Encoder and Variable Data Speed

The bi-directional voice service having variable data speed provides voice communication which employs
voice encoder algorithm having power variable data rate between the base station and the mobile station. On the
other hand, the transmit voice encoder performs voice sampling and then, creates encoded voice packets to be
sent out to the receive voice encoder, whereas the receive voice encoder demodulates the received voice packets
into voice samples.
One of the two voice encoders described in the above is selected for use depending on inputted automatic
conditions and message/data; both of them utilize four-stage frames of 9600, 4800, 2400, and 1200 bits per
second for Cellular and 14400,7200,3600,1800 bits per second for PCS, so PCS provide relatively better voice
quality (almost twice better than the existing celluar system). In addition, this type of variab le voice encoder
utilizes adaptive threshold values on selecting required data rate. It is adjusted in accordance with the size of
background noise and the data rate is increased to high rate only when the voice of caller is inputted.
Therefore, background noise is suppressed and high-quality voice transmission is possible under the
environment experiencing serious noise. In addition, in case the caller does not talk, data transmission rate is
reduced so that the transmission is carried out in low energy. This will reduce the interference on other CDMA
signals and as a result, improve system performance (capacity increased by about two times).

2.4 Protecting Call Confidentiality

Voice privercy is provided in the CDMA system by means of the private long code mask used for PN spreading.
Voice privacy can ve applied on the traffic channels only. All calls are initiated using the public long code mask
for PN spreading. The mobile station user may request voice privacy during call setup using the origination
message or page response message, and during traffic channel operation using the long code transition request
order.
The Transition to private long code mask will not be performed if authentication is not performed. To initiate a
transition to the private or public long code mask, either the base station or the mobile station sends a long code
transition request order on the traffic channel.

2.5 Soft Handoff

A handoff in which the mobile station commences communications with a new base station without interrupting
communications with the old base station. Soft handoff can only be used between CDMA channels having
identical freqeuncy assignments.

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2.6 Frequency Re-Use and Sector Segmentation

Unlike the existing analog Cellular system, the CDMA system can reuse the same frequency at the adjacent cell.
there is no need to prepare a separate frequency plan. Total interference generated on mobile station signals
received from the cell site is the sum of interference generated from other mobile stations in the same cell site
and interference generated from the mobile station of adjacent cell site. That is, each mobile station signal

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CX8700

generates interference in relation to the signals of all the other mobile stations .
Total interference from all the adjacent cell sites is the ratio of interference from all the cell sites versus total
interference from other mobile stations in the same cell site (about 65%). In the case of directional cell site, one
cell normally uses a 120°sector antenna in order to divide the sector into three. In this case, each antenna is
used only for 1/3 of mobile stations in the cell site and accordingly, interference is reduced by 1/3 on the average
and the capacity that can be supported by the entire system is increased by three times.

2.7 Soft Capacity

The subscriber capacity of the CDMA system is flexible depending on the relation between the number of
users and service classes. For example, the system operator can increase the number of channels available for
use during the busy hour despite the drop in call quality. This type of function requires 40% of normal call
channels in the standby mode during the handoff, in an effort to avoid call disconnection resulting from the lack
of channels.
In addition, in the CDMA system, services and service charges are classified further into different classes so that
more transmit power can be allocated to high class service users for easier call set-up; they can also be given
higher priority of using hand-off function than the general users.

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CX8700

3. Specification

3.1 General Specification

3.1.1 Transmit/Receive Frequency Interval :

1) CELLULAR : 45 MHz

2)

PCS : 80 MHz

3.1.2 Number of Channels (Channel Bandwidth)

1) CELLULAR : 20 Channels

2) PCS : 48 Channels

3.1.3 Operating Voltage : DC 3.3~4.2V

3.1.4 Battery Power Consumption : DC 3.7V

SLEEP IDLE MAX POWER

CELLULAR

PCS

1 mA 110~140mA 700 mA (24 dBm)
1 mA 120~150 mA 700 mA (24 dBm)

3.1.5 Operating Temperature : -20°C ~ +60°C

3.1.6 Frequency Stability

1) CDMA : ±0.5PPM

2) PCS : ±0.1PPM

3.1.7 Antenna : Intenna Type, 50 Ω

3.1.8 Size and Weight

1) Size : 97(H) * 49.5(W) * 13.6(D) mm

2) Weight : 110 g (Approximately with standard battery)

3.1.9 Channel Spacing

1) CELLULAR : 1.25MHz

2) PCS: 1.25 MHz

3.1.10 Battery Type, Capacity and Operating Time.

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Unit = Hours : Minutes

Standard (1,100mAh)

Standby Time

Talk time

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CELLULAR About 380 Hours (SCI=2)

PCS About 380 Hours (SCI=2)

CELLULAR 230 Minutes (-92dBm input)

PCS 230 Minutes (-92dBm input)

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CX8700

3.2 Receive Specification

3.2.1 Frequency Range

1) CELLULAR : 869.820 MHz ~ 893.190 MHz

2) PCS : 1930 MHz ~ 1990 MHz

3) GPS : 1575.42 MHz

3.2.2 Local Oscillating Frequency Range :

1) CELLULAR : 1738.08MHz ~ 1787.94MHz

2) PCS : 1715.56MHz ∼ 1768.89MHz

3) GPS : 3150.84MHz

3.2.3 Sensitivity

1) CELLULAR : -104dBm (C/N 12dB or more)

2) PCS : -104dBm (C/N 12dB or more)

3) GPS : -148.5dBm (without SA mode)

3.2.4 Selectivity

1) CELLULAR : 3dB C/N Degration (With Fch±1.25 kHz : -30dBm)

2) PCS : 3dB C/N Degration (With Fch±1.25 kHz : -30dBm)

3.2.5 Spurious Wave Suppression : Maximum of -80dB

3.2.6 CDMA Input Signal Range

z Dynamic area of more than -104~ -25 dB: 79dB at the 1.23MHz band.

3.3 Transmit Specification

3.3.1 Frequency Range

1) CELLULAR : 824.820MHz ~ 848.190MHz

2) PCS : 1850 MHz ~ 1910 MHz

3.3.2 Output Power

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1) CELLULAR : 0.224W

2) PCS: 0.224W

3.3.3 Interference Rejection

1) Single Tone : -30dBm at 900 kHz (CELLULAR), -30dBm at 1.25MHz(PCS)

2) Two Tone : -43dBm at 900 kHz & 1700kHz(CELLULAR), -43dBm at 1.25 MHz & 2.05 MHz
(PCS)

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CX8700

3.3.11 CDMA TX Frequency Deviation :

1) CELLULAR: +300Hz or less

2) PCS: ± 150Hz

3.3.12 CDMA TX Conducted Spurious Emissions

1) CELLULAR : 900kHz : - 42 dBc/30kHz below

1.98MHz : - 54 dBc/30kHz below

2) P C S : 1.25MHz : - 42 dBc/30kHz below

1.98MHz : - 50 dBc/30kHz below

3.3.13 CDMA Minimum TX Power Control

1) CELLULAR : - 50dBm below

2) P C S : -50dBm below

3.4

MS (Mobile Station) Transmitter Frequency

3.4.1 CELLULAR mode

Ch # Center Freq. (MHz) Ch # Center Freq. (MHz)

1011

29

70
111
152
193
234
275
316
363

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824.640

825.870

827.100

828.330

829.560

830.790

832.020

833.250

834.480

835.890

404
445
486
527
568
609
650
697
738
779

837.120

838.350

839.580

840.810

842.040

843.270

844.500

845.910

847.140

848.370

3.4.2 PCS mode

Ch # Center Freq (MHz) Ch # Center Freq (MHz) Ch # Center Freq (MHz)

25 1851.25 425 1871.25 825 1891.25
50 1852.50 450 1872.50 850 1892.50

75 1853.75 475 1873.75 875 1893.75
100 1855.00 500 1875.00 900 1895.00
125 1856.25 525 1876.25 925 1896.25
150 1857.50 550 1877.50 950 1897.50

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CX8700

175 1858.75 575 1878.75 975 1898.75
200 1860.00 600 1880.00 1000 1900.00
225 1861.25 625 1881.25 1025 1901.25
250 1862.50 650 1882.50 1050 1902.50
275 1863.75 675 1883.75 1075 1903.75
300 1865.00 700 1885.00 1100 1905.00
325 1866.25 725 1886.25 1125 1906.25
350 1867.50 750 1887.50 1150 1907.50
375 1868.75 775 1888.75 1175 1908.75

3.5

MS (Mobile Station) Receiver Frequency

3.5.1 CELLULAR mode

Ch. # Center Freq. (MHz) Ch. # Center Freq. (MHz)

1011

29

70
111
152
193
234
275
316
363

3.5.2 PCS mode

869.640

870.870

872.100

873.330

874.560

875.790

877.020

878.250

879.480

880.890

404
445
486
527
568
609
650
697
738
779

882.120

883.350

884.580

885.810

887.040

888.270

889.500

890.910

892.140

893.370

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Ch # Center Freq (MHz) Ch # Center Freq (MHz) Ch # Center Freq (MHz)

25 1931.25 425 1951.25 825 1971.25
50 1932.50 450 1952.50 850 1972.50

75 1933.75 475 1953.75 875 1973.75
100 1935.00 500 1955.00 900 1975.00
125 1936.25 525 1956.25 925 1976.25
150 1937.50 550 1957.50 950 1977.50
175 1938.75 575 1958.75 975 1978.75
200 1940.00 600 1960.00 1000 1980.00

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CX8700

225 1941.25 625 1961.25 1025 1981.25
250 1942.50 650 1962.50 1050 1982.50
275 1943.75 675 1963.75 1075 1983.75
300 1945.00 700 1965.00 1100 1985.00
325 1946.25 725 1966.25 1125 1986.25
350 1947.50 750 1967.50 1150 1987.50
375 1948.75 775 1968.75 1175 1988.75

3.5.3 GPS mode : 1575.42 MHz

3.5.4 Bluetooth mode : 2400 MHz ~ 2483.5 MHz

3.6 AC Adaptor : See Appendix

3.7 Cigar Lighter Charger : See Appendix

3.7 Hands – Free Kit : See Appendix

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CX8700

4. Installation

4.1 Installing a Battery Pack

1) The Battery pack is keyed so it can only fit one way. Align the groove in the battery pack with the rail on the
back of the phone until the battery pack rests flush with the back of the phone.

2) Slide the battery pack forward until you hear a “click”, which locks the battery in place.

4.2 For Adapter Use

1) Plug the adapter into a wall outlet. The adapter can be operated from a 110V source. When AC power is
connected to the adapter.

2) Insert the adapter IO plug into the phone with the installed battery pack.

Red light indicates battery is being charged.. Green light indicates battry is fully charged.

4.3 For Mobile Mount

4.3.1 Installation Position

In order to reduce echo sound when using the Hands-Free Kit, make sure that the speaker and microphone are
not facing each other and keep microphone a generous distance from the speaker.

4.3.2 Cradle Installation

Choose an appropriate flat surface where the unit will not interface with driver’s movement or passenger’s
comfort. The driver/user should be able to access the phone with ease. Using the four self-tapping screws
provided, mount the supplied braket on the selected area. Then with the four machine screws provided, mount
the counterpart on the reverse side of the reverse side of the cradle. Secure the two brackets firmly together by
using the two bracket joint screws provide. The distance between the cradle and the interface box must not
exceed the length of the main cable.

4.3.3 Interface Box

Choose an appropriate flat surface ( somewhere under the dash on the passenger side is preferred ) and mount
the IB bracket with the four self-tapping screws provided. Clip the IB into the IB bracket.

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4.3.4. Microphone Installation

Install the microphone either by cliiping I onto the sunvisor (driver’s side) or by attaching it to door post
(driver’s side), using a velcno adhesive tape (not included).

4.3.5 Cable Connections

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CX8700

4.3.5.1 Power and Ignition Cables

Connect the red wire to the car battery positive terminal and the black wire to the car ground. Connect the green
wire to the car ignition sensor terminal. ( In order to operate HFK please make sure to connect green wire to
ignition sensor terminal.) Connect the kit’s power cable connector to the interface box power receptacle.

4.3.5.2 Antenna Cable Connection

Connect the antenna coupler cable connector from the cradle to the external antenna connector. ( Antenna is not
included.)

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CHAPTER 2. NAM Input Method

(Inputting of telephone numbers included)

1. NAM Program Method and Telephone Number Inputting Method

1. In idle state, Press ‘##83587’ + “000000”

2. Select ‘1.NAM1’ or ‘2.NAM2’ to see each parameter.
(Except ESN)

● Usually pressing ‘OK key’ will save the change.

● To exit Service Program, press ‘END’ key.

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2-1) NAM1 Setting

After select ‘1.NAM1’, you can see this Entrance
screen for for NAM1 setting.
Press ‘OK key’ to edit NAM1 items.
Press ‘CLR key’ to go to the main page.
(NAM2 settingwill show you same screen when you
select ‘2.NAM2’)

2-2) NAM1 Phone Number (MDN)

You can edit NAM1 Phone Number(MDN).
Press ‘OK key’ to edit more NAM1 items.
Press ‘CLR key’ to edit previous NAM1 items.

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2-3) NAM1 Phone Number (MIN)

You can edit NAM1 Phone Number(MIN).
Press ‘OK key’ to edit more NAM1 items.
Press ‘CLR key’ to edit previous NAM1 items.

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2-4) NAM1 Home SID

You can edit NAM1 Home SID.
Press ‘OK key’ to edit more NAM1 items.
Press ‘CLR key’ to edit previous NAM1 items.

2-5) NAM1 Name

You can edit NAM1 Name.
Press ‘OK’ to edit more NAM1 items.
Press ‘Soft Key 1’ to edit NAM1 Name.
Press ‘CLR key’ to edit previous NAM1 items.

2-6) More NAM1 Programming

You can decide to edit more NAM1 items.
Press ‘END key’ to exit Service Programming.
Press ‘OK key’ to edit more advanced NAM1 items.

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2-7) NAM1 MCC

You can edit NAM1 Mobile Country Code.
Press ‘OK key’ to edit more NAM1 items.
Press ‘CLR key’ to edit previous NAM1 items.

2-8) NAM1 MNC

You can edit NAM1 MNC.
Press ‘OK key’ to edit more NAM1 items.
Press ‘CLR key’ to edit previous NAM1 items.

2-9) NAM1 NMSID

You can edit NAM1 MNC.
Press ‘OK key’ to edit more NAM1 items.
Press ‘CLR key’ to edit previous NAM1 items.

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2-10) NAM1 True IMSI MCC

You can edit NAM1 True IMSI MCC.
Press ‘OK key’ to edit more NAM1 items.
Press ‘CLR key’ to edit previous NAM1 items.

2-11) NAM1 True IMSI NMSID

You can edit NAM1 True IMSI NMSID.
Press ‘OK key’ to edit more NAM1 items.
Press ‘CLR key’ to edit previous NAM1 items.

2-12) NAM1 PRL Enabled

You can see NAM1 PRL Enabled.
Press ‘OK key’ to edit more NAM1 items.
Press ‘CLR key’ to edit previous NAM1 items.

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2-13) CDMA Home SID/NID

You can edit NAM1 Home SID/NID Pairs.
Press ‘OK key’ to edit more NAM1 items.
Press ‘CLR key’ to edit previous NAM1 items.

2-14) NAM1 CDMA Pri. CH A

You can edit NAM1 CDMA Primary Channel A.
Press ‘OK key’ to edit more NAM1 items.
Press ‘CLR key’ to edit previous NAM1 items.

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2-15) NAM1 CDMA Sec. CH A

You can edit NAM1 CDMA Secondary Channel A.
Press ‘OK key’ to edit more NAM1 items.
Press ‘CLR key’ to edit previous NAM1 items.

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2-16) NAM1 CDMA Pri. CH B

You can edit NAM1 CDMA Primary Channel B.
Press ‘OK key’ to edit more NAM1 items.
Press ‘CLR key’ to edit previous NAM1 items.

2-17) NAM1 CDMA Sec. CH B

You can edit NAM1 CDMA Secondary Channel B.
Press ‘OK key’ to edit more NAM1 items.
Press ‘CLR key’ to edit previous NAM1 items.

2-18) Lockout SID/NID

You can edit Lockout SID/NID Pairs.
Press ‘OK key’ to edit more NAM1 items.
Press ‘CLR key’ to edit previous NAM1 items.

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2-19) NAM1 Home Sys Reg

You can edit Home System Registration.
Press ‘OK key’ to edit more NAM1 items.
Press ‘CLR key’ to edit previous NAM1 items.
Press Left, Right, Up, Down key to toggle Yes/No.

2-20) NAM1 Forn SID Reg

You can edit NAM1 Foreign SID Registration.
Press ‘OK key’ to edit more NAM1 items.
Press ‘CLR key’ to edit previous NAM1 items.
Press Left, Right, Up, Down key to toggle Yes/No.

2-21) NAM1 Forn NID Reg

You can edit NAM1 Foreign NID Registration.
Press ‘OK key’ to edit more NAM1 items.
Press ‘CLR key’ to edit previous NAM1 items.
Press Left, Right, Up, Down key to toggle Yes/No.

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2-22) NAM1 Acc Ovld Class

You can see NAM1 Access Overload Class.
Press ‘OK key’ to edit more NAM1 items.
Press ‘CLR key’ to edit previous NAM1 items.

2-23) Slot Cycle Index

You can edit Slot Cycle Index
Press ‘OK key’ to edit more NAM1 items.
Press ‘CLR key’ to edit previous NAM1 items.

2-24) Powering Down

Restart.

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2-25) ESN

You can see the ESN number by select ‘3.View ESN’
from Service Programing main menu.
It will be shown as decimal format.
ESN can’t be modified.

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CX8700

CHAPTER 3. Circuit Description

1. RF Transmit/Receive Part

1.1 Overview

The TX and RX part employs the Direct-Conversion system. The TX and RX frequencies are
respectively 824.04~848.97 and 869.04~893.97 for cellular and 1850~1910 and 1930~1990 for
PCS. The block diagram is shown in [Figure 1-1]. RF signals received through the antenna are
seperated by the Triplexer.
RF Signal fed into the low noise amplifier in RFR6500(LNA) through the duplexer. Then, they are
fed into Mixer in RFR6500. In RFR6500, the RF signal is changed into baseband signal directly.
Then, this signal is changed into digital signal by the analog to digital converter (ADC, A/D
Converter), and the digital circuit part of the MSM(Mobile Station Modem) 6500 processes the
data from ADC. The digital processing part is a demodulator.
In the case of transmission, RFT6150 receives OQPSK-modulated anlaog signal from the
MSM6550.
The RFT6150 connects directly with MSM6550 using an analog baseband interface. In RFT6150,
the baseband quadrature signals are upconverted to the Cellular or PCS frequency bands and
amplified to provide signal drive capability to the power amp.
After that, the RF signal is amplified by the Power Amp in order to have enough power for
radiation. Finally, the RF signal is sent out to the cell site via the antenna after going through
the duplexer.

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CX8700

[Figure 1-1] Block Diagram of CX8700

Tri-band Ant.

U103

Mobile S/W

MS-156NB

Triplexer

GPS BPF

U104

Triplexer

C015

PCS Duplexer

ACMD-7402

DCN Duplexer

EFSD836MF2S2

DP101

U109

COUPLER

CP0402A1880

U110

COUPLER

CP0402A836

DP104

U107

GPS LNA

ALM-1106-TR1

U108

DUAL PAM

AWT6310R
Gain:27dB

Gain:15.9dB

NF:1.6dB

Gain:15.4dB

NF:1.4dB

Gain:15.4dB

NF:1.4dB

F104

PCS Tx RF BPF

ACPF -7002

IL:3.5dB

Attn.:35dB

F105
DCN Tx RF SAW
EFCH836MT CB 8

IL:2.5dB

Attn.:39dB

F102

PCS Rx RF SAW

B7847

IL:3.4dB

GPS Rx RF SAW

DCN Rx RF SAW
EFCH881MT CA7

IL:2.5dB

F103

B7840

F101

RFR6500

RFR6000

U105

RFT6150

RFT6150

TX PLL

Loop
Filter

LO Distribution

Loop
Filter

U102

Loop Filer

RX PLL

GPS PLL

Gain Control

X101

VCTCXO

TG-5010LH

LPF

LPF

LPF

Secondary path

Jammer Det.

SBI 1

SBI 1

SBI 2

Primary path

M

S

M

6
5
5
0

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CX8700

BLUETOOTH

RF

MODULE

RFT6150

VCTCXO

RFR6500

BT 1.2 PROCESS

JTAG Interface

ARM9 Core

R-UIM Controller

RF Interface

MSM6550

DFM processor

CDMA processor

gpsOne processor

Memory Controller

QDPS4000

- VOCODER

- MIDI(CMX) etc.

HK ADC

SBI

Tx DACs

PLL

Rx ADCs

CODEC

USB

GPIO

T-Flash MEMORY

CAMERA Module

2M Pixels

LCD MODULE

262K TFT Main

65K TFT Sub

PMIC

MAX1829

Battery

MCP MEMORY

1G NAND Flash

512M SDRAM

(TY9000A000AMGP)

KEYPAD

Mic

EARPIECE

Stereo SPK

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AUDIO AMP

(LM4857)

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CX8700

1.2 Description of RX Part Circuit

1.2.1 Triplexer Filter (U104)

The main function of Triplexer is to prohibit the other band signals from flowing into the one
band circuit and vice versa. RF designer can use common tri-band antenna regardless of
frequency band (800, 1575 and 1900 MHz). The specification of CX8700 Triplexer is described
below:

Cellular GPS PCS

Frequency Range 824 – 894 MHz 1575.42 MHz 1850 – 1990 MHz

Insertion Loss to

Common

Isolation

Temperature Range -30 to +85 deg

1.2.2 Duplexer (DP104, DP101)

1.0 dB Max

(At +25 deg)

48.5dB

(Cell TX)

1.8 dB Max.

(At +25 deg)

32.9dB(GPS-Cell)

18.3(GPS-PCS)

0.85 dB Max
(At +25 deg)

53.1dB

(PCS TX)

The duplexer consists of the RX bandpass filter (BPF) and the TX BPF which has the function of
separating TX and RX signals in the full duplex system for using the common antenna. The TX
part BPF is used to suppress noises and spurious out of the TX frequency band. The RX BPF is
used to receive only RX signal coming from the antenna, which is usually called preselector.
It’ s main function is to limit the bandwidth of spectrum reaching the LNA and mixer, attenuate
receiver spurious response and suppress local oscillator energy. As a result frequency
sensitivity and selectivity of mobile phone increase. The specification of CX8700 duplexer
described below ;

z PCS duplexer:

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TX RX TX to RX (min)

Pass Band 1850~1910 MHz 1930~1990 MHz

Insertion Loss 3.5dB max 3.0dB max

Return Loss 8.0dB min 8.0dB min

Attenuation

LG Electronics Inc.

(1930~1990MHz)

40dB min

50dB min

(1850~1910MHz)

54dB (1850~1910MHz)

44dB (1930~1990MHz)

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CX8700

z Cellular duplexer

TX RX TX to RX (min)

Pass Band 824~849 MHz 869~894 MHz

Insertion Loss 2.5B max 3.5dB max

VSWR 2.2 max 2.3 max

Attenuation 40dB min (869~894MHz)

1.2.3 LNA (U105)

The RFR6500 has cellular, and PCS LNA, respectively. The characteristics of Low Noise
Amplifier (LNA) are low noise figure, high gain, high intercept point and high reverse isolation.
The frequency selectivity characteristic of mobile phone is mostly determined by LNA.
The specification of CX8700 LNA is described below:

Parameter

Gain -19 -20 -2 -9 15.5 16 dB
Noise Figure 19 20 2 9 1.4 1.6 dB
Input IP3 25 25 20 20 6 8 dBm

1.2.4 GPS LNA(U107)

Low gain Middle gain High gain Units

Cellular PCS Cellular PCS Cellular PCS

50dB min

(824~849MHz)

54dB (824~849MHz)

43dB (869~894MHz)

The characteristics of Low Noise Amplifier (LNA) are low noise figure, high gain, high intercept
point and high reverse isolation. The frequency selectivity characteristic of mobile phone is
mostly determined by LNA.
The specification of CX8700 GPS LNA is described below

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Parameter GPS Band Units

Gain 14.8 dB

Noise Figure 0.85 dB

1dB compression point 0 dBm

IIP3 +5 dBm

1.2.5 RX RF SAW FILTER(F101, F102, F103)

The main function of RX RF SAW filter is to attenuate mobile phone spurious frequency,
attenuate noise amplified by the LNA and suppress second harmonic originating in the LNA.

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