Friday, May 3, 2013

Blackberry Tour 9630 PCB Schematic Diagram ..

NiCd charger circuits......

A simple NiCd charger can be built using ‘junk box’ components and an inexpensive LM317 or 78xx voltage regulator. Using a current limiter composed of R3 and a transistor, it can charge as many cells as desired until a ‘fully charged’ voltage determined by the voltage regulator is reached, and it indicates whether it is charging or has reached the fully charged state. If the storage capacitor (C1) is omitted, pulsed charging takes place. In this mode, a higher charging current can be used, with all of the control characteristics remaining the same. The operation of the circuit is quite simple. If the cells are not fully charged, a charging current flows freely from the voltage regulator, although it is limited by resistor R3 and transistor T1.

The limit is set by the formula Imax ≈ (0.6 V) ÷ R3 For Imax = 200 mA, this yields R3 = 3 Ω. The LED is on if current limiting is active, which also means that the cells are not yet fully charged. The potential on the reference lead of the voltage regulator is raised by approximately 2.9 V due to the voltage across the LED. This leads to a requirement for a certain minimum number of cells. For an LM317, the voltage between the reference lead and the output is 1.25 V, which means at least three cells must be charged (3 × 1.45 V > 2.9 V + 1.25 V). For a 78xx with a voltage drop of around 3 V (plus 2.9 V), the minimum number is four cells.

Circuit diagram.

When the cells are almost fully charged, the current gradually drops, so the current limiter becomes inactive and the LED goes out. In this state, the voltage on the reference lead of the regulator depends only on voltage divider R1/R2. For a 7805 regulator, the value of R2 is selected such that the current through it is 6 mA. Together with the current through the regulator (around 4 mA), this yields a current of around 10 mA through R1. If the voltage across R1 is 4 V (9 V – 5 V), this yields a value of 390 Ω. The end-of-charge voltage can thus be set to approximately 8.9 V. As the current through the regulator depends on the device manufacturer and the load, the value of R1 must be adjusted as necessary. The value of the storage capacitor must be matched to the selected charging current. As already mentioned, it can also be omitted for pulse charging.

Radiator temperature indicator Circuits.

This radiator temperature indicator can be designed using electronic circuit diagram bellow .Temperature indicator consists of two special zener diode, D1 and D2, connected in series to ensure accuracy of 5.96 V Zener voltage at 25 ° C. As long as the radiator temperature not exceeding 50 ° C, thermal indicator will flash a green LED, one orange will be provided for temperatures of 50 ... 75 ° C and a red LED, for temperatures above 75 ° C.

Zener voltage will increase by 20 mV for each temperature increase of a degree Celsius temperature. Radiator temperature corresponding voltage level is compared with two reference voltages, IC1 and IC2 using. When the temperature reaches 50 ° C, IC2's output goes to logic state "1" so that T3 leads and following ignition with diode D4. At 75 ° C, IC1's output is in logic state "1" and, therefore, T2 and T3 will, so that D3 and D4 lights are off. ------Radiator temperature indicator Circuits ----

Full duplex Intercom circuits.

No complex switching required

Simple circuitry, 6-12V supply

parts list .

P1_____________22K  Log. Potentiometer

R1_____________22K  1/4W Resistor
R2,R3_________100K  1/4W Resistors
R4_____________47K  1/4W Resistor
R5______________2K2 1/4W Resistor (See Notes)
R6______________6K8 1/4W Resistor
R7_____________22K  1/2W Carbon or Cermet Trimmer
R8______________2K7 1/4W Resistor

C1,C6_________100nF  63V Polyester or Ceramic Capacitors
C2,C3__________10µF  63V Electrolytic Capacitors
C4_____________22µF  25V Electrolytic Capacitor
C5_____________22nF  63V Polyester or Ceramic Capacitor
C7____________470µF  25V Electrolytic Capacitor

Q1____________BC547  45V 100mA NPN Transistor

IC1_________TDA7052  Audio power amplifier IC

SW1____________SPST  miniature Switch

MIC____________Miniature electret microphone

SPKR___________8 Ohm Loudspeaker

Screened cable (See Text)

This design allows to operate two intercom stations leaving the operator free of using his/her hands in some other occupation, thus avoiding the usual "push-to-talk" operation mode.
No complex changeover switching is required: the two units are connected together by means of a thin screened cable.
As both microphones and loudspeakers are always in operation, a special circuit is used to avoid that the loudspeaker output can be picked-up by the microphone enclosed in the same box, causing a very undesirable and loud "howl", i.e. the well known "Larsen effect".
A "Private" switch allows microphone muting, if required.

Circuit operation:

The circuit uses the TDA7052 audio power amplifier IC, capable of delivering about 1 Watt of output power at a supply voltage comprised in the 6 - 12V range.
The unusual feature of this design is the microphone amplifier Q1: its 180° phase-shifted audio output taken at the Collector and its in-phase output taken at the Emitter are mixed by the C3, C4, R7 and R8 network and R7 is trimmed until the two incoming signals almost cancel out. In this way, the loudspeaker will reproduce a very faint copy of the signals picked-up by the microphone.
At the same time, as both Collectors of the two intercom units are tied together, the 180° phase-shifted signal will pass to the audio amplifier of the second unit without attenuation, so it will be loudly reproduced by its loudspeaker.
The same operation will occur when speaking into the microphone of the second unit: if R7 will be correctly set, almost no output will be heard from its loudspeaker but a loud and clear reproduction will be heard at the first unit output.

Notes:

The circuit is shown already doubled in the diagram. The two units can be built into two separate boxes and connected by a thin screened cable having the length desired.
The cable screen is the negative ground path and the central wire is the signal path.
The power supply can be a common wall-plug adapter having a voltage output in the 6 - 12V dc range @ about 200mA.
Enclosing the power supply in the box of one unit, the other unit can be easily fed by using a two-wire screened cable, its second wire becoming the positive dc path.
To avoid a two-wire screened cable, each unit may have its own separate power supply.
Please note that R5 is the only part of the circuit that must not be doubled.
Closing SW1 prevents signal transmission only, not reception.
To setup the circuit, rotate the volume control (P1) of the first unit near its maximum and speak into the microphone. Adjust Trimmer R7 until your voice becomes almost inaudible when reproduced by the loudspeaker of the same unit.
Do the same as above with the second unit.

Fully Automatic Emergency Light Circuits

This simple automatic emergency light has the following advantages over conventional emergency lights:

The charging circuit stops automatically when the battery is fully charged. So you can leave the emergency light connected to AC mains overnight without any fear.
Emergency light automatically turns on when mains fails. So you don’t need a torch to locate it.
When mains power is available, emergency light automatically turns off.

The circuit can be divided into inverter and charger sections. The inverter section is built around timer NE555, while the charger section is built around 3-terminal adjustable regulator LM317. In the inverter section, NE555 is wired as an astable multivibrator that produces a 15kHz squarewave. Output pin 3 of IC 555 is connected to the Darlington pair formed by transistors SL100 (T1) and 2N3055 (T2) via resistor R4.

The Darlington pair drives ferrite transformer X1 to light up the tubelight. For fabricating inverter transformer X1, use two EE ferrite cores (of 25×13×8mm size each) along with plastic former. Wind 10 turns of 22 SWG on primary and 500 turns of 34 SWG wire on secondary using some insulation between the primary and secondary. To connect the tube-light to ferrite transformer X1, first short both terminals of each side of the tube-light and then connect to the secondary of X1. (You can also use a Darlington pair of transistors BC547 and 2N6292 for a 6W tube-light with the same transformer.

Circuit diagram

When mains power is available, reset pin 4 of IC 555 is grounded via transistor T4. Thus, IC1 (NE555) does not produce square-wave and emergency light turns off in the presence of mains supply. When mains fails, transistor T4 does not conduct and reset pin 4 gets positive supply though resistor R3. IC1(NE555) starts producing square wave and tube-light turns on via ferrite transformer X1. In the charger section, input AC mains is stepped down by transformer X2 to deliver 9V-0-9V AC at 500mA. Diodes D1 and D2 rectify the output of the transformer. Capacitors C3 and C4 act as filters to eliminate ripples.

The unregulated DC voltage is fed to IC LM317 (IC2). By adjusting preset VR1, the output voltage can be adjusted to deliver the charging voltage. When the battery gets charged above 6.8V, zener diode ZD1 conducts and regulator IC2 stops delivering the charging voltage. Assemble the circuit on a general-purpose PCB and enclose in a cabinet with enough space for the battery and switches. Connect a 230V AC power plug to feed charging voltage to the battery and make a 20W tube outlet in the cabinet to switch on the tube-light.

60 Watt Audio Power Amplifier Circuit Diagram .....

60 Watt Audio Power Amplifier Description

To celebrate the hundredth design posted to this website, and to fulfil the requests of many correspondents wanting an amplifier more powerful than the 25W MosFet, a 60 - 90W High Quality power amplifier design is presented here. Circuit topology is about the same of the above mentioned amplifier, but the extremely rugged IRFP240 and IRFP9240 MosFet devices are used as the output pair, and well renowned high voltage Motorola's transistors are employed in the preceding stages.
The supply rails voltage was kept prudentially at the rather low value of + and - 40V. For those wishing to experiment, the supply rails voltage could be raised to + and - 50V maximum, allowing the amplifier to approach the 100W into 8 Ohm target: enjoy! A matching, discrete components, Modular Preamplifier design is available here: Modular Audio Preamplifier.

Power Amplifier Circuits.

Parts List .

R1______________47K 1/4W Resistor
R2_______________4K7 1/4W Resistor
R3______________22K 1/4W Resistor
R4_______________1K 1/4W Resistor
R5,R12,R13_____330R 1/4W Resistors
R6_______________1K5 1/4W Resistor
R7______________15K 1/4W Resistor
R8______________33K 1/4W Resistor
R9_____________150K 1/4W Resistor
R10____________500R 1/2W Trimmer Cermet
R11_____________39R 1/4W Resistor
R14,R15_________R33 2.5W Resistors
R16_____________10R 2.5W Resistor
R17_____________R22 5W Resistor (wirewound)
C1_____________470nF 63V Polyester Capacitor
C2_____________470pF 63V Polystyrene or ceramic Capacitor
C3______________47µF 63V Electrolytic Capacitor
C4,C8,C9,C11___100nF 63V Polyester Capacitors
C5______________10pF 63V Polystyrene or ceramic Capacitor
C6_______________1µF 63V Polyester Capacitor
C7,C10_________100µF 63V Electrolytic Capacitors
D1___________1N4002 100V 1A Diode
D2_____________5mm. Red LED
Q1,Q2,Q4_____MPSA43 200V 500mA NPN Transistors
Q3,Q5________BC546 65V 100mA NPN Transistors
Q6___________MJE340 200V 500mA NPN Transistor
Q7___________MJE350 200V 500mA PNP Transistor
Q8___________IRFP240 200V 20A N-Channel Hexfet Transistor
Q9___________IRFP9240 200V 12A P-Channel Hexfet Transistor

Power supply circuits.

Parts:

R1_______________3K9 1W Resistor
C1,C2_________4700µF 63V Electrolytic Capacitors (See Notes)
C3,C4__________100nF 63V Polyester Capacitors
D1_____________400V 8A Diode bridge
D2_____________5mm. Red LED
F1,F2__________4A Fuses with sockets
T1_____________230V or 115V Primary, 30+30V Secondary 160VA Mains transformer
PL1____________Male Mains plug
SW1____________SPST Mains switch

Notes:

In the original circuit, a three-diode string was wired in series to R10. Two of these diodes are now replaced by a red LED in order to achieve improved quiescent current stability over a larger temperature range. Thanks to David Edwards of LedeAudio for this suggestion.
A small, U-shaped heatsink must be fitted to Q6 & Q7.
Q8 & Q9 must be mounted on large heatsinks.
Quiescent current can be measured by means of an Avo-meter wired in series to the positive supply rail and no input signal.
Set the Trimmer R10 to its minimum resistance.
Power-on the amplifier and adjust R10 to read a current drawing of about 120 - 130mA.
Wait about 15 minutes, watch if the current is varying and readjust if necessary.
The value suggested for C1 and C2 in the Power Supply Parts List is the minimum required for a mono amplifier. For optimum performance and in stereo configurations, this value should be increased: 10000µF is a good compromise.
A correct grounding is very important to eliminate hum and ground loops. Connect to the same point the ground sides of R1, R3, C2, C3 and C4 and the ground input wire. Connect R7 and C7 to C11 to output ground. Then connect separately the input and output grounds to the power supply ground.

Technical data:

Output power:
60 Watt RMS @ 8 Ohm (1KHz sinewave) - 90W RMS @ 4 Ohm
Sensitivity:
1V RMS input for 58W output
Frequency response:
30Hz to 20KHz -1dB
Total harmonic distortion @ 1KHz:
1W 0.003% 10W 0.006% 20W 0.01% 40W 0.013% 60W 0.018%
Total harmonic distortion @10KHz:
1W 0.005% 10W 0.02% 20W 0.03% 40W 0.06% 60W 0.09%
Unconditionally stable on capacitive loads.

10A Adjustable voltage Regulator MSK 5012 ..

MSK5012 is a highly reliable adjustable voltage regulator.Whose output can be programmed using two resistors. The regulator has a very low dropout voltage(0.45v @10A )due to the usage of MOSFET with very low Rds (ON) as the internal series pass element.The MS5012 has a high level of accuracy and ripple rejection is around 45dB. It is available in a 5 pin Sip package that is electrically isolated from the internal circuitry. This give us the freedom to fit the IC directly to the heat sink and this sort of direct heat sinking improves the thermal dissipation.

Description.

The output voltage of this circuit is adjustable from 1.3v to 36v DC.Resistors R₁ and R₂ are used for programming the output voltage.For all applications, value of R₂ is fixed to 10K. The relationship between R₁,R₂ and output voltage Vout is according to the equation R₁=R₂(Vout/1.235)-1. C₁ is a filter capacitor which is also a part of the gate drive circuit of the internal series pass MOSFET. Around three times the input voltage will appear across this capacitor and so the its voltage rating must be selected accordingly.C₂ is the input filter capacitor while C₃ is the output filter capacitor.

Circuit diagram.

Notes.

Input voltage 3v to 36v DC.
Output voltage range 13v to 36v DC.
Typical application of MSK5012 are high efficiency linear regulators, constant voltage/current regulators, system power supplies etc.
A heat sink with thermal resistance not more than 2.40 ^oC/W must be fitted to the MSK5012.
Resistance R₂ is fixed at 10 K for all applications.
Quiescent current of MSK5012 is around 10mA.

MOSFET Technology..

MOSFET Technology

This article focuses on basics of MOSFET Technology,basics of various MOS process like p-channel MOS (PMOS), n-channel MOS (NMOS), Complimentary MOS (CMOS) – its manufacturing, cross section, and other advantages of one over other.

Most of the LSI/VLSI digital memory and microprocessor circuits is based on the MOS Technology. More transistor and circuit functions can be achieved on a single chip with MOS technology, which is the considerable advantage of the same over bipolar circuits. Below given are the reasons for this advantage of MOS technology:

Less chip area is demanded by an Individual MOS transistor, which results in more functions in less area.
Critical defects per unit chip area is low for a MOS transistor because it involves fewer steps in the fabrication of a MOS transistor.
Dynamic circuit techniques are practical in MOS technology, but not in bipolar technology. A dynamic circuit technique involves use of fewer transistors to realise a circuit function.

So you are already clear that because of above said reasons, its considerably cheap to use MOS technology over Bipolar one.

Three types of MOS process are PMOS, NMOS and Complimentary MOS. Let’s take a look at brief descriptions below.

p-Channel MOS or PMOS Technology

This MOS process operates at a very low data rate say 200Kbps to 1Mbps. PMOS is also considered as the first MOS process which required special supply voltages as -9 volts, -12 volts and so on.

n-Channel MOS or NMOS Technology

We can say this is a second generation MOS process, after PMOS, which has considerable improvement in data rates; say up to 2Mbps and resulted in the construction of LSI circuits of a single standard +5volt supply.NMOS increases circuits speed in sharp, because of reduction in the internal dimensions of devices; which is contrary to (and an advantage over) bipolar circuits whose speed increases gradually.The difference in performance between both circuits have steadily become smaller for both LSI and VLSI because of steady improvements in pattern definition capability.

Have you ever heard of Self aligned silicon gate NMOS ? It’s a commonly used and popular version of MOS technology. Now a days, a technique named as local oxidation is used for this process to improve circuit density and performance. HMOS, SMOS and XMOS are the commonly used names by manufacturers for this. Older versions of the process like Metal Gate NMOS and PMOS are not used now a days for latest designs. A second layer of poly-silicon may be added to the process for important memory applications.

Complementary MOS Technology

So you might have already got an idea from the name “Complimentary MOS” ? Its a combination of both n-channel and p-channel devices in one chip. Compared to both other process, CMOS is complex in fabrication and requires larger chip area. Biggest advantage of a CMOS circuit is reduced power consumption (less than NMOS); it is designed for zero power consumption in steady state condition for both logic states. As you may already know, CMOS circuits are widely used in digital equipments like watches, computers etc.

CMOS offers comparatively higher circuit density and high speed performance (used in VLSI);and this is the primary reason why CMOS is still preferred despite it’s complex manufacturing process. Memories and microprocessors made of CMOS usually employ silicon gate process.

There are variations of MOS technology which offer either better performance or density advantages over the standard process. Some of those are named as VMOS (V-groove MOS), DSA (Diffusion Self Aligned), SOS (Silicon on Saphire), D-MOS (Double diffused MOS) etc.

Simple MOSFET Structures

MOS Technology comprises of 3 process basically, p-channel MOS, n-channel MOS and CMOS process. The basic purpose of all these process is to enhance MOSFET performance one over the other, like lower power consumption, high power capability, relaibility improvements, response speed etc.

PMOS Structure

The PMOS is the first device made in metal gate p-channel technology. PMOS infact is an older version of the MOS process which is not used nowadays. A cross sectional view of the PMOS structure is shown below.

The starting material is a single crystal Si that is doped n-type with phosphorus or antimony with a doping level on the order of 10¹⁵ atoms/cm³.

So the process is like this, first grow a relatively thick oxide layer; say 1.5micros and then etch windows for the source to drain diffusion. As a next step we have to boron dope the source and drain regions with 2 to 4 micro meters depth. Lets next form the gate oxide, that serves as the dielectric used for turning ON and OFF the MPS device. The entire circuit is then metalised and etched so that there is metal over the gate, drain, and the source. The metal layer should be 1 to 2 micrometers thick and is deposited using an electron beam evaporator.

NMOS Structure:

An NMOS structure also follows a similar pattern or sequence as shown in the crosssectional figure above; and is similar to PMOS except for the n+ regions which are diffused into the p-type silicon substrate.

Cable TV amplifier circuits.

Description.
This is a very simple cable TV amplifier using two transistors. This amplifier circuit is most suitable for cable TV systems using 75 Ohm coaxial cables and works fine up to 150MHz. Transistor T1 performs the job of amplification. Up to 20dB gain can be expected from the circuit.T2 is wired as an emitter follower to increase current gain.

Circuit diagram

Notes.

The circuit can be assembled on a Vero board.
Use 12V DC for powering the circuit.
Type no of the transistors are not very critical.
Any medium power NPN RF transistors can be used in place of T1 and T2.
This is just an elementary circuit. Do not compare it with high quality Cable TV amplifiers available in the market.

Introduction to GSM ....

Introduction

GSM is an acronym that stands for Global System for Mobile Communications. The original french acronym stands for Groupe Spécial Mobile. It was originally developed in 1984 as a standard for a mobile telephone system that could be used across Europe.

GSM is now an international standard for mobile service. It offers high mobility. Subscribers can easily roam worldwide and access any GSM network.

GSM is a digital cellular network. At the time the standard was developed it offered much higher capacity than the current analog systems. It also allowed for a more optimal allocation of the radio spectrum, which therefore allows for a larger number of subscribers.

GSM offers a number of services including voice communications, Short Message Service (SMS), fax, voice mail, and other supplemental services such as call forwarding and caller ID.

Currently there are several bands in use in GSM. 450 MHz, 850 MHZ, 900 MHz, 1800 MHz, and 1900 MHz are the most common ones.

Some bands also have Extended GSM (EGSM) bands added to them, increasing the amount of spectrum available for each band.

GSM makes use of Frequency Division Multiple Access (FDMA) and Time Division Multiple Access (TDMA).
*TDMA will be discussed later

[Back to Top]

Uplinks/Downlinks & Reverse Forward

GSM allows for use of duplex operation. Each band has a frequency range for the uplink (cell phone to tower) and a separate range for the downlink (tower to the cell phone). The uplink is also known as the Reverse and the downlink is also known as the Forward. In this tutorial, I will use the terms uplink and downlink.

Uplink and Downlink

[Back to Top]

Frequency Division Multiple Access (FDMA)

GSM divides the allocated spectrum for each band up into idividual carrier frequencies. Carrier separation is 200 khz. This is the FDMA aspect of GSM.

Absolute Radio Frequency Channel Number (ARFCN)

The ARFCN is a number that describes a pair of frequencies, one uplink and one downlink. The uplink and downlink frequencies each have a bandwidth of 200 kHz. The uplink and downlink have a specific offset that varies for each band. The offset is the frequency separation of the uplink from the downlink. Every time the ARFCN increases, the uplink will increase by 200 khz and the downlink also increases by 200 khz.

*Note: Although GSM operates in duplex (separate frequencies for transmit and receive), the mobile station does not transmit and receive at the same time. A switch is used to toggle the antenna between the transmitter and receiver.

The following table summarizes the frequency ranges, offsets, and ARFCNs for several popular bands.

GSM Bands

The following diagram illustrates an ARFCN with paired uplink and downlink frequencies for ARFCN 1 in the GSM 900 band.

GSM900 ARFCN 1

[Back to Top]

Calculating Uplink/Downlink Frequencies

The following is a way to calculate the uplink and downlink frequencies for some of the bands, given the band, the ARFCN, and the offset.

GSM 900

Up = 890.0 + (ARFCN * .2)
Down = Up + 45.0

example:

      Given the ARFCN 72, and we know the offset is 45MHz for the GSM900 band:
     Up = 890.0 + (72 * .2)
     Up = 890.0 + (14.4)
     Up = 904.40 MHz

     Down = Up + Offset
     Down = 904.40 + 45.0
     Down = 949.40 MHz

The uplink/downlink pair for GSM900 ARFCN72 is 904.40/949.40 (MHz)

Here are the formulas for EGSM900, DCS1800, and PCS1900:

EGSM900

Up = 890.0 + (ARFCN * .2)
Down = Up + 45.0

DCS1800

Up = 1710.0 + ((ARFCN - 511) * .2)
Down = Up + 95.0

PCS1900

Up = 1850.0 + ((ARFCN - 512) * .2)
Down = Up + 80.0

[Back to Top]

Numbering System (Identifiers)

Mobile Subscriber ISDN (MSISDN)

     The MSISDN is the subscriber's phone number. It is the number that another person would dial in order to reach the subscriber. The MSISDN is composed of three parts:
     Country Code (CC)
     National Destination Code (NDC)
     Subscriber Number (SN)

MSISDN

Country Code (CC) - This is the international dialing code for whichever country the MS is registered to.

National Destination Code (NDC) - In GSM, an NDC is assigned to each PLMN. In many cases, a PLMN may need more than one NDC.

Subscriber Number (SN) - This is a number assigned to the subscriber by the service provider (PLMN).

The combination of the NDC and the SN is known as the National (significant) Mobile Number. This number identifies a subscriber within the GSM PLMN.

National (significant) Mobile Number

[Back to Top]

International Mobile Subscriber Identity (IMSI)

     The IMSI is how the subscriber is identified to the network. It uniquely identifies the subscriber within the GSM global network. The IMSI is burned into the SIM card when the subscriber registers with PLMN service provider. The IMSI is composed of three parts:
     Mobile Country Code (MCC)
     Mobile Network Code (MNC)
     Mobile Subscriber Identification Number (MSIN)

IMSI

Mobile Country Code (MCC) - This number identifies which country the subscriber's network is in. It has 3 digits.

Mobile Network Code (MNC) - This number identifies the home GSM PLMN of the subscriber (Cingular, T-Mobile, etc.). It has 2 or 3 digits. Some networks may have more than one MNC allocated to it.

Mobile Subscriber Identification Number (MSIN) - This number uniquely identifies a user within the home GSM network.

[Back to Top]

International Mobile Equipment Identity (IMEI)

     The IMEI uniquely identifies the Mobile Equipment itself. It is essentially a serial number that is burned into the phone by the manufacturer. The IMEI is composed of three parts:
     Type Allocation Code (TAC) - 8 digits
     Serial Number (SNR) - 6 digits
     Spare (SP) - 1 digit

IMEI

Type Allocation Code (TAC) - This number uniquely identifies the model of a wireless device. It is composed of 8 digits. Under the new system (as of April 2004), the first two digits of a TAC are the Reporting Body Identifier of the GSMA approved group that allocated this model type.

Serial Number (SNR) - This number is a manufacturer defined serial number for the model of wireless device.

Spare (SP) This number is a check digit known as a Luhn Check Digit. It is omitted during transmission within the GSM network.

On many devices the IMEI number can be retrieved by entering *#06#

Former IMEI Structure

Prior to April, 2004 the IMEI had a different structure:
     Type Allocation Code (TAC) - 6 digits
     Factory Assembly Code (FAC) - 2 digits
     Serial Number (SNR) - 6 digits
     Spare (SP) - 1 digit

Former IMEI Structure

As of April 2004, the use of the FAC was no longer required. The current practice is for the TAC for a new model to get approved by national regulating bodies, known as the Reporting Body Identifier.

[Back to Top]

International Mobile Equipment Identity/Software Version (IMEISV)

     This is a newer form of the IMEI that omits the Spare digit at the end and adds a 2-digit Software Version Number (SVN) at the end. The SVN identifies the software version that the wireless device is using. This results in a 16-digit IMEI.
     Type Allocation Code (TAC) - 8 digits
     Serial Number (SNR) - 6 digits
     Software Version Number (SVN) - 2 digits