LG KC780 User manual

Service Manual Model : KC780
Internal Use Only
Service Manual
KC780
Date: January, 2009 / Issue 1.1

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Copyright © 2008 LG Electronics. Inc. All right reserved.
Only for training and service purposes
LGE Internal Use Only
REVISED HISTORY
Editor Date Issue Contents of Changes S/W Version
Y.G.KIM 08/27 0.1

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Copyright © 2008 LG Electronics. Inc. All right reserved.
Only for training and service purposes
LGE Internal Use Only
Table Of Contents
1. INTRODUCTION...............................................9
1.1 Purpose......................................................................9
1.2 Regulatory Information.................................................9
2. PERFORMANCE............................................. 11
2.1 H/W Feature..............................................................11
2.2 Technical specification ...............................................12
3. TECHNICAL BRIEF......................................... 18
3.1 KC780 Component Block diagram..............................18
3.2 Main Chip Introduction...............................................19
3.3 Baseband Part Introduction ........................................21
3.4 Power Management Unit............................................32
3.5 Power ON/OFF ..........................................................36
3.6 SIM interface.............................................................39
3.7 Memory ....................................................................40
3.8 LCD Display ..............................................................41
3.9 Keypad Switching & Scanning ....................................43
3.10 Keypad back-light illumination..................................45
3.11 LCD back-light illumination ......................................45
3.12 JTAG interface connector.........................................48
3.13 Audio......................................................................49
3.14 USB charging circuit ................................................53
3.15 BLUETOOTH............................................................54
3.16 FM Radio ................................................................56
3.17 Micro SD external memory card slot .........................57
3.18 18pin Multi Media Interface connector......................59
3.19 General Description .................................................61
3.20 Receiver part...........................................................62
3.21 Transmitter part.......................................................63
3.22 RF synthesizer.........................................................64
3.23 DCXO .....................................................................64
3.24 Front End Module control.........................................64
3.25 Power Amplifier Module ...........................................66
3.26 Mode Selection .......................................................66
4. PCB layout.................................................... 67
4.1 Main PCB component placement................................67
5. TROUBLE SHOOTING..................................... 71
5.1 Trouble shooting test setup ........................................71
5.2 Power on Trouble.......................................................72
5.3 Charging trouble........................................................75
5.4 LCD display trouble ...................................................77
5.5 Camera Trouble.........................................................80
5.6 Receiver & Speaker trouble........................................82
5.7 Microphone trouble ...................................................84
5.8 Ear-MIC Jack Detection trouble ..................................85
5.9 Vibrator trouble..........................................................86
5.10 Keypad back light trouble.........................................87
5.11 SIM & uSD trouble...................................................90
5.12 RF Troubleshooting ..................................................94
5.13 RF Receiver path Troubleshooting.............................99
5.14 RF Transmitter path Troubleshooting .......................102
6. Download & S/W upgrade .........................107
6.1 S/W download setup................................................107
6.2 Download program user guide..................................108
7. BLOCK DIAGRAM........................................ 110
8. CIRCUIT DIAGRAM...................................... 111
9. BGA Pin Map ..............................................121
10. PCB LAYOUT .............................................127
11. RF Calibration .......................................... 137
11.1 Test Equipment Setup............................................137
11.2 Calibration Step.....................................................137
12. STAND-ALONE TEST .................................142
12.1 Test Program Setting .............................................142
12.2 Tx Test..................................................................144
12.3 Rx Test..................................................................145
13. ENGINEERING MODE................................. 147
14. EXPLODED VIEW & REPLACEMENT
PART LIST ................................................. 149

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LGE Internal Use Only Copyright © 2008 LG Electronics. Inc. All right reserved.
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* The information in this manual is subject to change without notice and should not be construed
as a commitment by LGE Inc. Furthermore, LGE Inc. reserves the right, without notice, to make
changes to equipment design as advances in engineering and manufacturing methods warrant.
* This manual provides the information necessary to install, program, operate and maintain the
KC780.
ABBREVIATION
For the purposes of this manual, following abbreviations apply:
◆
APC Automatic Power Control
◆
BB Baseband
◆
BER Bit Error Ratio
◆
CC-CV Constant Current – Constant Voltage
◆
CLA Cigar Lighter Adapter
◆
DAC Digital to Analog Converter
◆
DCS Digital Communication System
◆
dBm dB relative to 1 milli-watt
◆
DSP Digital Signal Processing
◆
EEPROM Electrical Erasable Programmable Read-Only Memory
◆
EGPRS Enhanced General Packet Radio Service
◆
EL Electroluminescence
◆
ESD Electrostatic Discharge
◆
FPCB Flexible Printed Circuit Board
◆
GMSK Gaussian Minimum Shift Keying
◆
GPIB General Purpose Interface Bus
◆
GPRS General Packet Radio Service
◆
GSM Global System for Mobile Communications
◆
IPUI International Portable User Identity
◆
IF Intermediate Frequency
◆
LCD Liquid Crystal Display
◆
LDO Low Drop Output
◆
LED Light Emitting Diode
◆
LGE LG Electronics
◆
OPLL Offset Phase Locked Loop
◆
PAM Power Amplifier Module
◆
PCB Printed Circuit Board
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◆
PGA Programmable Gain Amplifier
◆
PLL Phase Locked Loop
◆
PSTN Public Switched Telephone Network
◆
RF Radio Frequency
◆
RLR Receiving Loudness Rating
◆
RMS Root Mean Square
◆
RTC Real Time Clock
◆
SAW Surface Acoustic Wave
◆
SIM Subscriber Identity Module
◆
SLR Sending Loudness Rating
◆
SRAM Static Random Access Memory
◆
STMR Side Tone Masking Rating
◆
TA Travel Adapter
◆
TDD Time Division Duplex
◆
TDMA Time Division Multiple Access
◆
UART Universal Asynchronous Receiver/Transmitter
◆
VCO Voltage Controlled Oscillator
◆
VCTCXO Voltage Control Temperature Compensated Crystal
Oscillator
◆
WAP Wireless Application Protocol
◆8PSK 8 Phase Shift Keying

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Copyright © 2008 LG Electronics. Inc. All right reserved.
Only for training and service purposes
LGE Internal Use Only
1. INTRODUCTION
1. INTRODUCTION
1.1. Purpose
This manual provides the information necessary to repair, calibration, description and download
the features of the KC780.
1.2. Regulatory Information
1.2.1. Security
Toll fraud, the unauthorized use of telecommunications system by an unauthorized part (for
example, persons other than your company’s employees, agents, subcontractors, or person
working on your company’s behalf) can result in substantial additional charges you’re your
telecommunications services. System users are responsible for the security of own system.
There are may be risks of toll fraud associated with your telecommunications system. System
users are responsible for programming and configuring the equipment to prevent unauthorized
use. LGE does not warrant that this product is immune from the above case but will prevent
unauthorized use of common-carrier telecommunication service of facilities accessed through or
connected to it. LGE will not be responsible for any charges that result from such unauthorized
use.
1.2.2. Incidence of Harm
If a telephone company determines that the equipment provided to customer is faulty and
possibly causing harm or interruption in service to the telephone network, it should disconnect
telephone service until repair can be done. A telephone company may temporarily disconnect
service as long as repair is not done.
1.2.3. Changes in Service
A local telephone company may make changes in its communications facilities or procedure. If
these changes could reasonably be expected to affect the use of the KC780 or compatibility with
the network, the telephone company is required to give advanced written notice to the user,
allowing the user to take appropriate steps to maintain telephone service.

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LGE Internal Use Only Copyright © 2008 LG Electronics. Inc. All right reserved.
Only for training and service purposes
1. INTRODUCTION
1.2.4. Maintenance Limitations
Maintenance limitations on the KC780 must be performed only at the LGE or its authorized
agents. The user may not make any changes and/or repairs expect as specifically noted in this
manual. Therefore, note that unauthorized alternations or repair may affect the regulatory status
of the system and may void any remaining warranty.
1.2.5. Notice of Radiated Emissions
The KC780 complies with rules regarding radiation and radio frequency emission as defined by
local regulatory agencies. In accordance with these agencies, you may be required to provide
information such as the following to the end user.
1.2.6. Pictures
The pictures in this manual are for illustrative purposes only; your actual hardware may look
slightly different.
1.2.7. Interference and Attenuation
An KC780 may interfere with sensitive laboratory equipment, medical equipment, etc.
Interference from unsuppressed engines or electric motors may cause problems.
1.2.8. Electrostatic Sensitive Devices
ATTENTION
Boards, which contains Electrostatic Sensitive Device(ESD), are indicated by the sign.
Following information is ESD handling: Service personnel should ground themselves by using a
wrist strap when exchange system boards.
When repairs are made to a system board, they should spread the floor with anti-static mat
which is also grounded. Use a suitable, grounded soldering iron. Keep sensitive parts in these
protective packages until these are used. When returning system boards or parts such as
EEPROM to the factory, use the protective package as described.

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Copyright © 2008 LG Electronics. Inc. All right reserved.
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2. PERFORMANCE
2. PERFORMANCE
2.1 H/W Feature
Item Feature Comment
Standard Battery Li-ion, 900mAh
AVG TCVR Current 260mA typ @PL5
Standby Current 2 mA typ @PP9
Talk time 6 hours (GSM TX Level 10)
Standby time Over 450 hours (Paging Period:9, RSSI:
-85dBm)
Charging time Under 3 hours
RX Sensitivity EGSM : -105dBm↓, DCS/PCS : -105dBm↓
TX output power EGSM : 33dBm (@PL 5)
DCS/PCS: 30dBm (@PL 0)
GPRS compatibility Class 12
SIM card type 3V Small
Display 240 u320 pixels, 2.4 inch QVGA, 262K color,
TFT
Status Indicator
Soft icons, 0 a9, #, *, Scroll, Send, End/PWR,
Clear AF/Camera double action, Volume Up,
Volume Down
ANT Built in antenna
EAR Phone Jack 18pin multi port Headset jack (W/O remote
controller)
PC Synchronization Yes
Speech coding HR/EFR/FR/AMR
Data and Fax Yes
Vibrator Yes
Buzzer No
Voice Recoding Yes
C-Mic Yes
Receiver Yes
Travel Adapter Yes
Options Bluetooth hands-free kit, Data Kit

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2. PERFORMANCE
2.2 Technical specification
Item Description Specification
1Frequency Band
EGSM
TX: 890 + 0.2 x n MHz
RX: 935 + 0.2 x n MHz ( n = 1 ~ 124 )
TX: 890 + 0.2 x (n-1024) MHz
RX: 935 + 0.2 x (n-1024) MHz ( n = 975 ~ 1023 )
DCS1800
TX: 1710 + ( n-511 ) u0.2 MHz (n = 512 a885)
RX: TX + 95 MHz
PCS1900
TX: 1850.2 + ( n-512 ) u0.2 MHz (n = 512 a810)
RX: TX + 80MHz
2Phase Error RMS < 5 degrees , Peak < 20 degrees
3Frequency Error < 0.1ppm
EGSM
Level Power Toler. Level Power Toler.
5 33 dBm ±2dB 13 17 dBm ±3dB
6 31 dBm ±3dB 14 15 dBm ±3dB
7 29 dBm ±3dB 15 13 dBm ±3dB
8 27 dBm ±3dB 16 11 dBm ±5dB
9 25 dBm ±3dB 17 9 dBm ±5dB
10 23 dBm ±3dB 18 7 dBm ±5dB
11 21 dBm ±3dB 19 5 dBm ±5dB
12 19 dBm ±3dB
DCS1800/PCS1900
Level Power Toler. Level Power Toler.
0 30 dBm ±2dB 8 14 dBm ±3dB
1 28 dBm ±3dB 9 12 dBm ±4dB
2 26 dBm ±3dB 10 10 dBm ±4dB
3 24 dBm ±3dB 11 8 dBm ±4dB
4 22 dBm ±3dB 12 6 dBm ±4dB
5 20 dBm ±3dB 13 4 dBm ±4dB
6 18 dBm ±3dB 14 2 dBm ±5dB
4Power Level
7 16 dBm ±3dB 15 0 dBm ±5dB

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Copyright © 2008 LG Electronics. Inc. All right reserved.
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LGE Internal Use Only
2. PERFORMANCE
EGSM
Offset from Carrier (kHz). Max. dBc
100 +0.5
200 -30
250 -33
400 -60
600 ~ 1,200 -60
1,200 ~ 1,800 -60
1,800 ~ 3,000 -63
3,000 ~ 6,000 -65
6,000 -71
DCS1800/PCS1900
Offset from Carrier (kHz). Max. dBc
100 +0.5
200 -30
250 -33
400 -60
600 ~ 1,200 -60
1,200 ~ 1,800 -60
1,800 ~ 3,000 -65
3,000 ~ 6,000 -65
5
Output RF Spectrum
(due to modulation)
6,000 -73
EGSM
Offset from Carrier (kHz) Max. (dBm)
400 -19
600 -21
1,200 -21
1,800 -24
DCS1800/PCS1900
Offset from Carrier (kHz) Max. (dBm)
400 -22
600 -24
1,200 -24
6
Output RF Spectrum
(due to switching transient)
1,800 -27

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LGE Internal Use Only Copyright © 2008 LG Electronics. Inc. All right reserved.
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2. PERFORMANCE
7 Spurious Emissions Conduction, Emission Status
Conduction, Emission Status
8Bit Error Ratio
EGSM
BER (Class II) < 2.439% @-102dBm
DCS1800/PCS1900
BER (Class II) < 2.439% @-100dBm
9Rx Level Report accuracy r3 dB
10 SLR 8r3 dB
Frequency (Hz) Max.(dB) Min.(dB)
100 -12 /
200 0 /
300 0 -12
1,000 0 -6
2,000 4 -6
3,000 4 -6
3,400 4 -9
11 Sending Response
4,000 0 /
12 RLR 2r3 dB
Frequency (Hz) Max.(dB) Min.(dB)
100 -12 /
200 0 /
300 2 -7
500 * -5
1,000 0 -5
3,000 2 -5
3,400 2 -10
4,000 2
13 Receiving Response
* Mean that Adopt a straight line in between
300 Hz and 1,000 Hz to be Max. level in the
range.
14 STMR 13 r5 dB
15 Stability Margin > 6 dB
dB to ARL (dB) Level Ratio (dB)
-35 17.5
-30 22.5
-20 30.7
-10 33.3
16 Distortion
0 33.7

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Copyright © 2008 LG Electronics. Inc. All right reserved.
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2. PERFORMANCE
7 31.7
10 25.5
17 Side tone Distortion Three stage distortion < 10%
18 <Change> System frequency (26 MHz)
tolerance d2.5 ppm
19 <Change>32.768KHz tolerance d30ppm
20 Power consumption Standby
- Normal，d2 mA(@PP9)
21 Tal k Ti m e EGSM/Lvl 7 (Battery Capacity 900mA):180min
EGSM/Lvl12(Battery Capacity 900mA): 320min
22 Standby Time
Under conditions, at least 300 hours:
1. Brand new and full 900mAh battery
2. Full charge, no receive/send and keep GSM
in idle mode.
3. Broadcast set off.
4. Signal strength display set at 3 level above.
5. Backlight of phone set off.
23 Ringer Volume
At least 65 dB under below conditions:
1. Ringer set as ringer.
2. Test distance set as 50 cm
24 Charge Current TA Charge : < 450 mA
USB Charge: <200 mA
Antenna Bar Number Power
7-92 dBm 이상 a
7 -> 5 -93 ± 2dBm
5 -> 4 -98 ± 2dBm
4 -> 2 -101 ± 2dBm
2 -> 1 -104 ± 2dBm
25 Antenna Display
1 -> 0 -106 ± 2dBm
Battery Bar Number Voltage (±0.05V)
3 3.76V~4.2V
2 3.68V~3.75V
1 3.55V~3.65V
26 Battery Indicator
0 3.41V~
3.58V↓±0.05V (Call)
27 Low Voltage Warning 3.51V↓±0.05V (Standby)

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2. PERFORMANCE
28 Forced shut down Voltage 3.35 r0.05 V
29 Battery Type
Li-ion Battery
Standard Voltage = 3.7 V
Battery full charge voltage = 4.2 V
Capacity: 900mAh
30 Travel Charger
Switching-mode charger
Input: 100 a240 V, 50/60Hz
Out put: 5.1, 0.7A
* EDGE RF Specification (Option: is not serviced for ”EDGE mode”)
Item Description Specification
1 RMS EVM ≤9%
2 Peak EVM ≤30%
3 95th Percentile EVM ≤15%
4 Origin Offset Suppression ≥30dB
EGSM
Level Power Toler. Level Power Toler.
5 27dBm ±3dB 13 17dBm ±3dB
6 27dBm ±3dB 14 15dBm ±3dB
7 27dBm ±3dB 15 13dBm ±3dB
8 27dBm ±3dB 16 11dBm ±5dB
9 25dBm ±3dB 17 9dBm ±5dB
10 23dBm ±3dB 18 7dBm ±5dB
11 21dBm ±3dB 19 5dBm ±5dB
12 19dBm ±3dB
DCS1800, PCS1900
Level Power Toler. Level Power Toler.
0 26dBm ±3dB 8 14dBm ±3dB
1 26dBm ±3dB 9 12dBm ±4dB
2 26dBm ±3dB 10 10dBm ±4dB
3 24dBm ±3dB 11 8dBm ±4dB
4 22dBm ±3dB 12 6dBm ±4dB
5 20dBm ±3dB 13 4dBm ±4dB
6 18dBm ±3dB 14 2dBm ±5dB
5 Power Level
7 16dBm ±3dB 15 0dBm ±5dB
EGSM
Offset from carrier(kHz) Max. dBc
100 +0.5
200 -30
250 -33
400 -54
6 Output RF Spectrum
(due to modulation)
600~<1,200 -60

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Copyright © 2008 LG Electronics. Inc. All right reserved.
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2. PERFORMANCE
1,200~<1,800 -60
1,800~<3,000 -63
3,000~<6,000 -65
6,000 -71
DCS1800, PCS1900
Offset from carrier(kHz) Max. dBc
100 +0.5
200 -30
250 -33
400 -54
600~<1,200 -60
1,200~<1,800 -60
1,800~<3,000 -63
3,000~<6,000 -65
6,000 -71
EGSM
Offset from carrier(kHz) Max. dBm
400 -23
600 -26
1,200 -27
1,800 -30
DCS1800, PCS1900
Offset from carrier(kHz) Max. dBm
400 -23
600 -26
1,200 -27
7Output RF Spectrum
(due to switching transient)
1,800 -30

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3. TECHNICAL BRIEF
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2. PERFORMANCE
III-1 Baseband circuit
3.1. KC780 Component Block diagram.
KC780 is composed with 5 different PCB part such as main PCB, Key PCB, Key FPCB, LCD FPCB and
Flash FPCB
The functional component arrangement is mentioned below diagram.
Figure 1 KC780 Functional block diagram
8M
2012
module
8bit parallel I/F
2
1Gb
LMSP43NA-7
82
3. TECHNICAL BRIEF

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Copyright © 2008 LG Electronics. Inc. All right reserved.
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3. TECHNICAL BRIEF
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Copyright © 2008 LG Electronics. Inc. All right reserved.
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LGE Internal Use Only
3. TECHNICAL BRIEF
3.2. Main Chip Introduction
Figure 2 Application View of the S-GOLDradioTM Block Diagram
3.2.1. General Description
1.1 Introduction
With the latest member of the S-GOLD family, S-GOLDradioTM, Infineon Technologies introduces the
world’s first single-chip solution for feature-rich mobile phones. The EDGE-capable device combines all
digital and analog functions of the baseband, a quad-band RF transceiver, and the power management
circuitry into a single chip. With an option for memory stacking (“Package on Package”, JEDEC compliant)
the key functions of a mobile phone are now combined into a single device, providing all the benefits that
come from a maximum level of integration. Full software re-use from the proven Infineon EDGE platform,
MP-ELite, enables fast time-to-market using a comprehensive development kit available to all customers
today.
S-GOLDradioTM is tailored to fit the requirements of EDGE-enabled feature phones with a standard set of
multimedia applications such as:
• Still picture imaging up to 2 MPixel

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3. TECHNICAL BRIEF
• MPEG4 video encode/decode
• Video streaming
• MP3 playback
• Java applications.
This single chip solution allows for very small form factor phones with a high degree of power efficiency.
Its low cost structure makes multimedia feature-enhanced EDGE phones very affordable for
price-sensitive market segments. S-GOLDradioTM’s small footprint, competitive cost position, and low
power consumption also makes it the perfect fit for EDGE-capable data cards.
S-GOLDradioTM’s baseband processing is powered by an ARM926EJ-S CPU and a TEAKLite® DSP core.
The ARM926EJ-S is a powerful standard controller and particularly suited for wireless systems. It is
supported by a wide range of tools and application SW.
The TEAKLite® is an established DSP core for wireless applications with approved firmware for GSM
signalprocessing. The Infineon Technologies DSP firmware and software modules for FR, HR, EFR and
AMR-NB vocoding and channel encoding allow a short time to market. Additionally, S-GOLDradioTM
supports multislot operation modes:
HSCSD (up to class 10), GPRS for high speed data applications (up to class 12) and EGPRS (up to class
12) without additional external hardware.
A wide choice of communication interfaces allows complex data and multimedia system designs.
Furthermore, S-GOLDradioTM contains its own Power Supply and Battery Management. Its design is
optimized forall mobile platform needs (such as graphic displays with backlights) and internal needs
(analog components, loudspeaker, USB, etc.). S-GOLDradioTM is driven directly from re-chargeable
batteries such as Li-Ion or Li-Polymer batteries. S-GOLDradioTM Power Management provides different
supply voltages by using highly efficient
DCDC converters, DCDC boost converters and linear, low-dropout regulators (LDOs). In addition, it
supports battery charging, generates stand-by voltages and supports different low power modes.
The S-GOLDradioTM RF capability features a quad-band transceiver for
EGSM/GSM900/GSM1800/GSM1900, and it is designed for voice and data transfer applications. Its
architecture consists of a direct conversion receiver and a quad-band polar transmitter for GSM/EDGE.
Accurate output power setting is ensured by an integrated power control loop, which supports linear and
non-linear power amplifiers. The entirely integrated quad-band RF
oscillator and Sigma-Delta synthesizer give the S-GOLDradioTM HSCSD and GPRS/EDGE capabilities.
Figure 2 shows a typical application example: The S-GOLDradioTM as a single chip solution acting as a
multifunctional engine in a complete mobile phone platform.

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Copyright © 2008 LG Electronics. Inc. All right reserved.
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3. TECHNICAL BRIEF
3.3. Baseband Part Introduction
Figure 3 S-GOLDradioTM Baseband Block Diagram
3.3.1. Block Description
Connectivity
S-GOLDradioTM offers a variety of connectivity options common in today’s feature phone applications:
• USB 2.0 Full Speed (12 Mbps)
• IrDA Controller
Supports Infrared SIR Mode Transceivers
• RS-232 over a 16C550 compliant UART
• MMC/SD Memory Card Interface