ABBERVATIONS USED IN CELLPHONETECHNOLOGY

Definition of Abbreviations on Mobile Phones Circuit

0
2G  2nd Generation

3G 3rd Generation

3Gs 3rd Generation speed

4G 4th Generation

A
A/D-converter Analog-to-digital converter

ACI Accessory Control Interface

ADC Analog-to-digital converter

ADSP Application DPS (expected to run high level tasks)

AGC Automatic gain control (maintains volume)

ALS Ambient light sensor

AMSL After Market Service Leader

ARM Advanced RISC Machines

ARPU Average revenue per user (per month or per year)

ASIC Application Specific Integrated Circuit

ASIP Application Specific Interface Protector

B
B2B Board to board, connector between PWB and UI board

BB Baseband

BC02 Bluetooth module made by CSR

BIQUAD Bi-quadratic ,type of filter function)

BSI Battery Size Indicator

BT Bluetooth

C
CBus MCU controlled serial bus connected to UPP_WD2,UEME and Zocus

CCP Compact Camera Port

CDSP Cellular DSP (expected to run at low levels)

CLDC Connected limited device configuration

CMOS Complimentary metal-oxide semiconductor circuit (low power consumption)

COF Chip on Foil

COG Chip on Glass

CPU Central Processing Unit

CSR cambridge silicon radio

CSTN Color Super Twisted Nematic

CTSI Clock Timing Sleep and interrupt block of Tiku

CW   Continuous wave

D
D/A-converter   Digital-to-analouge converter

DAC Digital-to-analouge converter

DBI  Digital Battery Interface

DBus DSP controlled serial bus connected between UPP_WD2 and Helgo

DCT-4 Digital Core Technology

DMA  Direct memory access

DP    Data Package

DPLL Digital Phase Locked Loop

DSP Digital Signal Processor

DtoS Differential to Single ended

E
EDGE Enhanced data rates for global/GSM evaluation

EGSM Extended GSM

EM Energy management

EMC Electromagnetic compability

EMI Electromagnetic interference

ESD Electrostatic discharge

F
FCI Functional cover interface

FPS Flash Programming Tool

FR Full rate

FSTN Film compensated super twisted nematic

G
GND Ground, conductive mass

GPIB General-purpose interface bus

GPRS General Packet Radio Service

GSM Group Special Mobile/Global System for Mobile communication

H
HF Hands free

HFCM Handsfree Common

HS Handset

HSCSD High speed circuit switched data (data transmission connection faster than GSM)

HW Hardware

I
I/O Input/Output

IBAT Battery current

IC Integrated circuit

ICHAR Charger current

IF Interface

IHF Integrated hands free

IMEI International Mobile Equipment Identity

IR Infrared

IrDA Infrared Data Associasion

ISA Intelligent software architecture

J
JPEG/JPG Joint Photographic Experts Group

L
LCD Liquid Crystal Display

LDO Low Drop Out

LED Light-emitting diode

LPRF Low Power Radio Frequency 

M
MCU Micro Controller Unit (microprocessor) 

MCU Multiport control unit 

MIC, mic Microphone 

MIDP Mobile Information Device Profile 

MIN Mobile identification number 

MIPS Million instructions per second 

MMC Multimedia card 

MMS Multimedia messaging service 

N
NTC Negative temperature coefficient, temperature sensitive resistor used as a 

temperature sensor 

O
OMA Object management architechture 

OMAP Operations, maintenance, and administartion part 

Opamp Operational Amplifier 

P
PA Power amplifier 

PDA Pocket Data Application 

PDA Personal digital assistant 

PDRAM Program/Data RAM (on chip in Tiku) 

Phoenix Software tool of DCT4.x 

PIM Personal Information Management 

PLL Phase locked loop 

PM (Phone) Permanent memory 

PUP General Purpose IO (PIO), USARTS and Pulse Width Modulators 

PURX Power-up reset 

PWB Printed Wiring Board 

PWM Pulse width modulation 

R
RC-filter Resistance-Capacitance filter 

RF Radio Frequency 

RF PopPort TM Reduced function PopPortTM interface 

RFBUS Serial control Bus For RF 

RSK Right Soft Key 

RS-MMC Reduced size Multi Media Card 

RSSI Receiving signal strength indicator 

RST Reset Switch 

RTC Real Time Clock (provides date and time) 

RX Radio Receiver 

S
SARAM Single Access RAM 


SAW filter Surface Acoustic Wave filter 

SDRAM Synchronous Dynamic Random Access Memory 

SID Security ID

SIM Subscriber Identity Module 

SMPS Switched Mode Power Supply

SNR Signal-to-noice ratio 

SPR Standard Product requirements 

SRAM Static random access memory 

STI Serial Trace Interface

SW Software 

SWIM Subscriber/Wallet Identification Module

T
TCXO Temperature controlled Oscillator 

Tiku Finnish for Chip, Successor of the UPP, Official Tiku3G 

TX Radio Transmitter

U
UART Universal asynchronous receiver/transmitter

UEME Universal Energy Management chip (Enhanced version)

UEMEK See UEME 

UI User Interface 

UPP Universal Phone Processor

UPP_WD2Communicator version of DCT4 system ASIC

USB Universal Serial Bus


V
VBAT Battery voltage 

VCHAR Charger voltage 

VCO Voltage controlled oscillator 

VCTCXO Voltage Controlled Temperature Compensated Crystal Oscillator 

VCXO Voltage Controlled Crystal Oscillator

Vp-p Peak-to-peak voltage 

VSIM SIM voltage

W
WAP Wireless application protocol 

WD Watchdog

X
XHTML Extensible hypertext markup language


Z
Zocus Current sensor, (used to monitor the current flow to and from the battery)

FLASHING AND UNLOCKING

Flashing is installing a new firmware to  a cellphone flash memory. When the cellphones firmware is being damaged or interrupted, this one particularly result on not powering the phone, hang up, or keep on re-starting and a lot more software problem issues.
This firmwares were comes with different versions.
 Each mobile phones product has unique firmware versions. And have also specific software that to be use for it.
If you have a basic computer knowledge is more advantage, but even if none you can still do and learn easily.
What things do we need in flashing cellphones?
In flashing phones we need ob-course
1.)A desktop or laptop computer to run the software program, with a USB (universal serial bus) port.
2.) Flashing Device- It is programmed circuit that can synchronize the mobile phone and the computer.
3. Flashing Software - this software is provided by the flashing device seller or even you can download it on the internet.
4. A USB cable and a flashing Cable wire- this the wire that used to connect the mobile phones to the flashing device that also connect to the computer.
This one is also provided by the flashing devices seller or you can purchased a pre designed one.
Every mobile phone products have different kinds of flashing devices used,  and also have different methods and procedures.
5. Flashfiles and Firmware collection- this are the programmed data used in the phones. See here of exmples of flashfiles in Nokia Mobile Phones.
Below are the list of Flashing devices which is being used to flash a certain and particular mobile phone products.

Advance-Box
Axe Box
Cruiser Team Products
CPF-box Products
Cyclonebox
Easy-Unlocker
ET-BoX
FuriouS TeaM Products
Genie Universal
GM-Box
GsmMagicBox G
SMServer Products
Infinity-Box
J.A.F - Just Another Flasher
Kulankendi Box / Dongle
Martech products
Mastertools
McnPro Box
Micro-Box.com Team Products
Multi-Box TEAM Products
MXKEY (by Alim Hape)
NEROkey
NSPRO
POLAR Team Products
Rocker Team products
T-BOX Products
SAGEM JTAG UNLOCKER
Saras Boxes
SMTi Support Sections
SpiderMan
SPT BOX
Super Doctor Box (MTK-BOX)
TEST-BOX 2
TGT Products
Ultimate-Sam
Universalbox
UST Pro II
Ve Box
Vodafone Star
VygisToolbox
Z3X-Team Products

UNLOCKING

There are many mobile phones are "locked" into one particular service provider once purchased it. A user cannot use the handset to switch into another service provider by replacing available SIM card module into it.
So the best reason is to unlock the phone so it will be used into another network which is very useful when traveling from country to country.
Unlocking is completely legal and not illegal, because every phone user own the phone after all! 
the only reasons that the networks do it is to try to make sure that the phone users don't move to another network, but all it really does is stop them using the phone as they would like to!

But how to Unlock a Phone?
 There are two methods in unlocking mobile phones, It varies a certain products of mobile phones some can be easily unlock and some are not.
1. Unlocking by entering an unlock code. Many Nokia, Samsung, Siemens, Sony, Panasonic and some other brands of mobile phone will unlock if you enter a specific code based on your phone's IMEI (serial) number. This is the most easy method of unlocking - all you have to do is get hold of the code!
There are some that offers free unlock codes and some you need to purchased it via online.

2. If a model of phone does not support unlocking by code, you need to get the phone unlocked using a unlocking device and a unlocking software tool.

BASIC MOBILE PHONES HARDWARE REPAIR TROUBLESHOOTING TECHNIQUES

Fixing hardware problems is not been easy and takes a lot of time to consume rather than software problems, it is because when it comes to software handling you don't really need to open or dismantle a mobile phone handset, because only few of them really need to. In most cases like this, many among mobile phones technician focus on software handling like especially unlocking, for it less time consuming and more flexible to do with. This is been true that mobile phone technicians were separated into two specialties, like Hardware expert and Software expert, that is what the term they called it; It because mobile phones is a combination of software and hardware mechanism.
But there are also many mobile phones masters that can manage and do both hardware and software specialty and skills. They gained this knowledge by years of experience, and not only that they also earned much more income rather than to those staying at one particular specialty.

Now, here is the basic step by step repair procedure on hardware troubleshooting on mobile phones. Various mobile phones have different circuits and components or parts layouts and designs. First thing you must learn and be familiar with is, how each circuit components or parts is being mounted, connected, assembled or designed.


First step in handling troubleshooting procedure.
1. Visualization Checkup- Before proceeding to anything always consider the fact that a mobile phones handset is fragile object. Check and have take a look around every inch of the handsets package and layout, In this manner you can identify if the handset is in repairable condition, something like checking the whole printed circuit board components and parts, if it is free from dust,corrosion, bended,breakage etc.
2. Know the Phones Status - Ask the the user or the costumer about the phones history before the problem occurs. Letting know the phones history like accidentally soaked into a liquids or water, dropped,throwned and etc.
In this manner you can get an idea where to start or begin with.
3. Do Software Check up - Use a certain flashing device for that particular handset product to be able to read logs, logs is a reading of mobile phones firmware programmed and installed unto it. This is a big help for most advance mobile technician this days, A logs reading can help you where the faulty line or parts occurs. If you are not familiar about how to read logs you can ask to that certain flashing device product supporters and creator.
You can do flash, reformat at first hand if found something wrong with the mobile phones firmware. If all methods of software already done and nothing happens, proceed to hardware troubleshooting.

4. Analyze The Circuit - After dismantling and do visualization check up,be patient and take your time to analyze the whole circuits layout, and think of a step by step plan procedure in your mind where or how to begin with. A Special Operation Procedure is good way and a reliable source of idea within yourself, not only by enhancing your skills but you are also practicing a self discipline method.

Now lets take one example of basic hardware troubleshooting methods in one particular mobile phone handsets. In this simple way you can then manage how to troubleshoot or been able on finding faulty parts or components within a mobile phone circuitry.

An example here is Nokia 6300, now assuming that this handset having a faulty microphone or mouthpiece.

Do the basic procedures mentioned above, assuming that you are familiar with the  Mouthpiece or microphone circuit, and already  know how to check a microphone or mouthpiece component.
you can now do this step below;

1. Find any available schematic diagram and locate the microphone circuit layout on it. Remember where each parts and components location and do a mapping like this.

2. Use a multi-tester and check the pads for a short circuit, this is not always happen but it is also unpredictable to a mobile phones short circuit might occurs, you are not checking the outer mounted components but the internal lines with it. Just set the tester to x1 resistance value, I preferred analog multitester in this lesson for it is cheaper to purchase rather than the digital. Now connect both test probe to the inner and outer layer of the mouthpiece terminal pads, then do it again in opposite manner, a short circuit have both readings closer to zero ohms.

3. Trace the line paths between the first or the closest component connected to each terminal pads.
The circuit diagram shows that there are coil filter in both lines, connect the tester across each coil terminal leds, your not just checking the lines here but alsochecking the the coil as well.

4. Now the next step is to leave behind the line paths between the coil to the EMI-Filter for it is uncheckable beyond that paths for the EMI- filter is an IC. you need to remove it first before you can check on that lines , which will be done later at the last steps of procedures. Now next to move on to the opening lines and component where the test probe can connect with, the two filter capacitors and both coils which are an open path where you can connect the test probe on it. now connect or attach both probes at the end of each line indicated in red.

5. Now check the remaining open path which is the Resistor, you can't check the line paths on those area for it ends up connected to Retu IC. So just then proceed to check its resistance value instead.

6. If all those mentioned lines above is all in good condition you may now proceed to suspect the EMI-Fiter is having a problem or faulty. You then now remove it from the Printed circuit board then do a line check up from the mouthpiece terminal to that EMI-filter terminal bumps where it is being connected.

You can refer to the schematic diagram for each terminal specification. You may now can check the IC itself by analyzing the internal circuitry inside it. I advice just replace a good and working one if not so sure about.

8. It this step is most complicated job to do with, specially for beginners.This is one of advance troubleshooters skills.  If found all of those line paths and components above were in good conditions. The last part is to work a power management IC itself for the audio codec circuit is also within that chips.
Now, if the last and final suspected parts is the chips, you must need to rework it, Reheating it the first will do and might as well also work. But if the problem still remain, Reworking it is the best advice that suites out.
but also do not forget to check the line paths between the mouthpiece circuit area, while the chips is being remove and out on the PCB layout, it is a proper time to check the ball bumps terminal where that certain microphone is being connected. an example of tracing the ball bumps terminals below.

okay, that's it for a while, for there are lots of techniques we are going to tackle sooner, hope you do understand a little bit with this method.

HOW RF CIRCUIT WORKS?

In cell phone repair it is very helpful to understand how the RF circuits works , for this is a big help when
troubleshooting No signal problem issues.
RF stands for radio frequency , this frequency is used to  transmit and receive the data signals from a mobile phone.

Here's a brief explanation on how does RF circuit works on mobile phones. 
This is for GSM RF circuit only, although the WCDMA circuit and WI-FI circuit have similarity on this but I will try to explain both of it hereafter. 

See the block diagram below. Observe how the frequency data signal feeds from a certain parts of an RF circuit design. 
A breakdown or failure of each certain part will result to signal loss and the capability to generate, amplify, control , process, send and receive the desired radio frequency during transmission process.  


In mobile phones transmission there are two types of operation took place, the receiving operation and the transmitting operation.
In normal mode, RX part is always active in receiving operation the antenna switch is always open its gateway through to the RX circuit, It is always ready to receive and intercepts the radio waves and wait for the desired frequency signal to catch up.
During transmission like making a call or sending a text message the antenna switch will close the gateway of the RX and open the gateway of the TX in order not to interfere the data signal during transmission.
All data that has been receive and before to transmit or send, all this data signals are feeds to the baseband processor.

An explanation  of an RF Circuit Parts and what possible problems if a certain part is damaged. 

RF Receiver - ( RX radio receiver )
The rf receiver are called RX, this circuit is design to receives, and process the data signals from the airwaves during transmission process. A failure of this circuit will result to unable to receive data signal during transmission. 

RF Transmitter  - ( TX radio transmitter )
the rf transmitter are called TX which is the one that process, amplify  the data signals from a mobile phone .  
Once failed to initiate  a failure to transmit radio frequency signal, this will result to unable to send data signal during transmission. .

Power amplifier -  RF amplifier
The power amplifier is used to amplify, boost up the radio frequency signal before it feeds to the antenna before it thrown over the air waves during transmission. If damaged will result to signal loss, a dropping signal indication on the display.

The Antenna is used to intercepts and thrown the radio radio frequency in the air  during transmission
When electricity is "thrown" into the metal of an antenna, the metal reacts to the electricity at an atomic level in the form of a wave.
if damaged or due to a corroded terminal pads, will indicate and show a poor signal or low level frequency signal.

Antenna switch
The antenna switch is used as a gateway that controls and manage the frequency to pass through, it switch the RX frequency signal and TX frequency signal during transmission process. literally  the antenna is the signal catcher and likewise the signal thrower. If damaged the gateway to the antenna will be closed and result to network signal indication.  

Crystal oscillator
Generates a desired frequency that feeds to the RX and TX circuits. In mobile phones a Voltage controlled Oscillator (VCO) and Voltage Controlled Temperature Compensated Crystal Oscillator (VCTXO) is used in rf circuit. 
If damaged the RX and TX will not work and the RF cicuit is at full failure.

SAW filter 
Surface Acoustic Wave filter used as an rf synthesizer to purify  a desired level of frequency. If damaged result also to no network signal indication. 

An example of the  RF circuit components layout on a PCB board.

The rf circuit components are often covered with shielding metal case unlike the baseband processor parts which is oftentimes not. This is because frequency is very vulnerable with unwanted radio waves interference and destroys data signals. Using the shielding metal will minimize the radio waves interference.