MMC (TC) Lab Manual 2009

PRACTICAL WORK BOOK For Academic Session 2009

MULTIMEDIA COMMUNICATION

(TC-497)

For B.E (TC)

Name:

Roll Number:

Batch:

Department:

Year :

Department of Electronic Engineering

NED University of Engineering & Technology, Karachi

LABORATORY WORK BOOK For The Course TC-497 Multimedia Communication

Prepared By: Ms. Nida Nasir (Lecturer) & Muhammad Fahim Ul Haque (Lecturer)

Reviewed By: Mr. Tahir Malik(Lecturer)

Approved By:

The Board of Studies of Department of Electronic Engineering

INTRODUCTION

Multimedia Communication Practical Workbook covers those practical that

are very knowledgeable and quite beneficial in grasping the core objective of

the subject. These practical solidify the theoretical and practical concepts

that are very essential for the engineering students.

This work book comprise of practical covering the topics of Multimedia

communication that are arranged on modern trainer boards. Above all this

workbook contains a relevant theory about the Lab session.

Contents NED University of Engineering & Technology- Department of Electronic Engineering

Telecommunications Laboratory

CONTENTS

Lab No.

DATED List of Experiments Page No. Remarks

1 To connect & control Bluetooth module 1-4

2

To control DC & STEP motor, power control module using BT 5-7

3 To control temperature sensor & infra red sensor 8-10

4 To control touch sensor & ultrasonic sensor 11-12

5 To control gas, pressure, humidity sensor 13-14

6 To examine the operation of CD player 15-17

7 To examine fault simulation of CD player 18-19

8 To examine the operation of DVD player 20-24

9 To examine fault simulation of DVD player 25-26

10 To check the operation of VTR 27-29

11

To become familiar with use of 4 telephones connected to local switching center 30-32

12 To become familiar with time & space switching 33-35

13

i.Determined the relationship between information held within the control memory and the actual switching operation.

ii.Established the procedure to connect tones to calling lines.

36-39

Contents NED University of Engineering & Technology- Department of Electronic Engineering

Telecommunications Laboratory

CONTENTS

Lab No.

DATED List of Experiments Page No. Remarks

14 To learn how call state, call record, call progress are made 40-43

15 To become familiar with call progress assignment 44-47

Multimedia Communication _ NED University of Engineering & Technology- Department of Electronic Engineering

LAB SESSION 01

OBJECT: A) To introduce the parts of Bluetooth modules. B) To connect and control Bluetooth modules. THEORY & PROCEDURE: 1) System Connection BT-3000 connection between the program and hardware is communicated through USB. When a command is sent to server hardware from the server program, the server hardware performs wireless communication with slave hardware and controls module that is mounted on a slave. As shown in the figure, the server and slave communicate wirelessly and the operation differs depending on the connected slave module. 2) Module Connection Mount a module to be used in Con3 and Con4 practice on the right side of slave board. All used modules are mounted here. When a user created his/her own module, it has to be tested for power connector and ground before mounting. Total 13 modules are given here. The serial number of module that is used in practice ranges from BT-3000-04 ~ 16 are as follows; BT-3000-4 : DC Motor Module BT-3000-5 : Step Motor Module BT-3000-6 : Regular Power Control Module BT-3000-7 : Current Power Control Module BT-3000-8 : Temperature Sensor Control1 Module BT-3000-9 : Temperature Sensor Control2 Module BT-3000-10 : Infrared Sensor Control1 Module BT-3000-11 : Infrared Sensor Control2 Module BT-3000-12 : Touch Sensor Control Module BT-3000-13 : Ultrasonic Sensor Control Module BT-3000-14 : Gas Sensor Control Module BT-3000-15 : Humidity Sensor Control Module BT-3000-16 : Pressure Sensor Control Module When mounting the module, the module must be placed so that the module serial number can be seen from the left or parts numbers must be seen clearly. If the direction of module is incorrect, it cannot be mounted on the board.

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Multimedia Communication _ NED University of Engineering & Technology- Department of Electronic Engineering Con1 and Con2 in the center are connectors that mount the controller. The currently provided controller can be used with other PIC controller that has same pin arrangement. For this system, highly expandable controller has been selected for future integration. In near future, 8051 series and ARM series processors will be supported. The controller is created in socket format so that various CPU types can be used for different user types. 3) Slave Board Parts Description a) Bluetooth Chipset part This part controls the communication to the slave. On the slave board, Class1 Bluetooth chipset is used to enable nearby wireless communications. When a user becomes familiar with programming, server side also can be embedded to reduce the communication distance limitation. b) Interface part The interface part of a slave board can be used to individually learn Bluetooth chipset or to load a program onto mycom. Direct programming through UART is not yet supported. c) LED part This part is used to check the currently operating slave status. This part is largely divided into two parts. LED part1 displays the operation status of Mycom and Bluetooth, and LED part2 is a LED that notifies the type of currently connected modules. When a user mounts a power group or a motor group onto a slave board, Mycom recognizes the mounted module and displays a respective LED. IDLE: In this status, only power is supplied to Bluetooth and no communication are being processed. CONN: This status shows that the device is in connection with a server. d) Power & Audio part BT-3000 system uses various powers to operate numerous sensors. Main power supplied to a slave board is provided in adopter format and uses 9V, 1A. Also, for voice communication during basic communication practices, audio jack (ear-microphone jack) is attached. Wireless Control Wireless communication is not as easy as it seems and the procedure is also complicated. These procedures are organized with BT-3000. In wireless control a user will learn how to communicate two devices wirelessly. It is composed of the following four practices.

Inquiry for nearby devices ACL Connection (data communication connection)

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SCO Connection (voice communication connection) Command Input (basic command repeat practice)

1) Inquiry for nearby devicesIn this, a user will learn how to inquire other devices located in nearby network using Bluetooth. Practice is processed in the following order. Step 1: Equip server hardware and slave hardware as shown in the connection diagram. Step 2: Make sure that a controller and a practice module is connected to a slave board before supply power to slave side. Step 3: When device setup is completed, turn on the power. Step 4: Run the server program. Program is located in Windows Start menu Step 5: Press the button located on the right top corner of the main screen. Step 6: Click Search Near by Devices Button located on the bottom right corner. Step 7: The server starts inquiring nearby Bluetooth devices. Step 8: When the search is complete, the server program displays searched slave devices on screen. The list gives the addresses of Bluetooth devices that responded. NONAME in the list means that no name has been recorded to the slave Bluetooth chip. The blank on top of the list is used to display the address of selected device. The names of provided systems are not recorded, and if there are any other Bluetooth devices nearby, the names of those devices appear. 2) ACL Connection- Asynchronous connection Less (Data Communication Connection) The connection process for communication between two Bluetooth devices is studied. All procedures after inquiring all nearby devices is done using search function. Step 1 to Step 8: Same as nearby device search. Step 9: Select a device from the searched devices screen. Step 10: Select an address from nearby device selection screen and click basic practice button. Step 11: From ACL connection screen, click ACL connection button among the two buttons. Step 12: When the connection button is successfully pressed, the connection release button on the right of the connection button is activated. In this step, a user can send data that can control the module mounted on a slave board. 3) SCO Connection Synchronous Connection Oriented (Voice Communication Connection) Bluetooth requires ACL connection for voice communication with a slave device. Step 1 to Step 12: Repeat steps in point 1 & 2. Step 13: After ACL data connection, press basic practice button for SCO connection and select SCO connection menu from wireless control basic practice screen.

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Multimedia Communication _ NED University of Engineering & Technology- Department of Electronic Engineering Step 14: Click SCO connection button located on the bottom of the screen and try voice communication. 4) Command Input Bluetooth commands used in HCI Layer are practiced using hexa-code that fits USB communication method. A user will be able to understand slave Bluetooth programming commands through this procedure. Also, a user will learn commands that initialize Bluetooth, or change a device to a slave/server. Step 1: Click Wireless Basic Control Practice button on main screen Step 2: Select command input menu Step 3: Enter a correct command using the command input box on the bottom of screen. RESULT:

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LAB SESSION 02

OBJECT: A) To control DC and Step motor modules using BT devices. B) To control power & current power modules using BT devices. REQUIRED DEVICES:

Server Hardware Server Program Slave Hardware (PN:BT-3000-1) Controller Module (PN:BT-3000-2) DC Motor Module (Appl 1, PN:BT-3000-4) Step Motor Module (Appl 2, PN:BT-3000-5) Regular Power Control Module (Appl 3, PN:BT-3000-6) Current Power Control Module (Appl 4, PN:BT-3000-7) PIC Compiler (CCS-C)

THEORY: DC motor module receives a signal from a server and rotate/reverse-rotate the motor. A user must refer to the provided circuit diagram to learn about the module properties, and then write a PIC series controller program to confirm the normal operation of a module. Motor Control A user who has completely understood the previous practices will write a program that controls DC motor and step motor from a remote location. Make sure to understand the operating environment with the provided hardware and code and then follow practice procedures. Power Control Power control practice is used to learn how to control power. A user will learn how to turn on/off power, to control current in adjusting brightness of lighting type power. A user should learn the operation type using the provided module and write a slave side controller program. Power Control module receives data from a server and turns on/off LED remotely. A user should analyze the server data and control the LED of a power module. In addition, wireless communication program needs to be created as well.

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Multimedia Communication _ NED University of Engineering & Technology- Department of Electronic Engineering Current power module controls the current and adjusts the brightness. A user should analyze data received from a server and write a program that adjusts the brightness of the light bulb. PROCEDURE: 1) DC Motor Control For DC motor control, the following procedures need to be followed. Step 1: Mount DC motor Control module on to a slave board and turn on the power. Step 2: Run nearby device search of wireless control basic practice. Step 3: Run ACL Connection of wireless control practice Step 4: When ACL connection is made, a message that shows the DC motor module connection appears on the bottom of the screen. Then click motor control practice button on the right of the screen. Step 5: When motor Control practice button is selected, the button is deactivated. When DC motor practice menu is selected, DC motor practice screen appears. In this screen, click the button on the bottom to control DC motor. The leftmost button rotates the motor in reverse direction and the rightmost button rotates the motor in forward direction. The operation of the motor may vary depending on the users program. Every time a button is clicked, slave side DC motor forward/reverse rotates. On screen, the shutter moves up/down. Step 6: When the practice is over, click the return button located on the button of the right buttons to move to the initial screen. Here, the connection with slave side is also automatically disconnected. 2) Step motor control Step 1: Mount step motor control module onto a slave board and turn on the power. Step 2: Run nearby device search of wireless control basic practice. Step 3: Run ACL connection of wireless control basic practice. Step 4: When ACL connection is made, a message that notifies step motor module connection appears. Then, click motor control practice button on the right side of screen and select step motor practice menu to display practice initial screen. Step 5: Two buttons on the bottom of screen rotates a step motor forward/reverse direction. When this button is pressed, the step motor rotates in designated direction and the screen changes. Step 6: When practice is completed, press the return button on the bottom of the right buttons and move to initial screen. Here, the connection with the slave side is also released. 3) Regular Power Control This practice is about coding a program that turns on/off the remote power. A user will learn how to control power while communicating wirelessly with a server.

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Multimedia Communication _ NED University of Engineering & Technology- Department of Electronic Engineering Step 1: Mount regular power control module on to a slave board and turn on the power. Step 2: Run nearby device search of wireless control basic practice. Step 3: Run ACL Connection of wireless control practice. Step 4: When ACL connection is made, a message that shows the power control module connection appears on the bottom of the screen. Then click regular power control practice button on the right of the screen. Step 5: When the four toggle switch of the screen is clicked, four LED on the slave board are turned ON/OFF. When the toggle switch is ON, the light bulb of the screen is lit as well as the LED on the slave board. Step 6: When the practice is completed, press return button to move to initial screen. The slave side connection is also automatically released. 2) Current Power Control Current Power Control Practice is done in the following order. Step 1: Mount current power control module on to a slave board and turn on the power. Step 2: Run nearby device search of wireless control basic practice. Step 3: Run ACL Connection of wireless control practice. Step 4: When ACL connection is made, a message that shows the power control module connection appears on the bottom of the screen. Then click current power control practice button on the right of the screen. Step 5: Two buttons on the left/right side of the screen adjust the brightness of light bulbs. A user can adjust the brightness using this button. A user should write a program that analyzes the data received from a server and adjusts the brightness. Step 6: When the practice is completed, press return button to move to initial screen. The slave side connection is also automatically released. RESULT:

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LAB SESSION 03

OBJECT:

i. To control Temperature Sensor 1 & 2 modules using BT devices ii. To control Infrared Sensor 1 & 2 modules using BT devices

REQUIRED DEVICES:

Server Hardware Server Program Slave Hardware (PN:BT-3000-1) Controller Module (PN:BT-3000-2) Temperature Sensor Control1 Module (Appl 5, PN:BT-3000-8) Temperature Sensor Control2 Module (Appl 6, PN:BT-3000-9) Infrared Sensor Control1 Module (Appl 7, PN:BT-3000-10) Infrared Sensor Control2 Module (Appl 8, PN:BT-3000-11) PIC Compiler (CCS-C)

THEORY: Sensor Control In sensor control practice, total 9 different sensors can be tested. A user will practice how to read the sensor value with different sensors. Set up a threshold to produce alarm when it goes over the threshold, and check any changes in the surrounding. Temperature sensor 1 module retrieves the temperature sensors analog temperature and uses the data in alarm or living environment control. A user should write a program that can transfer temperature data to a server based on server request. Temperature sensor 2 module measures the nearby temperature digitally and operates devices such as a fan. A user should write a code that measures exact temperature and notify the server. Infrared sensor 1 module detects the disconnection of a signal when an object is placed between two sensors. When an object is detected, the situation is depicted on the screen. A user should write a program that notifies the disconnection of a signal to a server. Infrared sensor 2 module detects human body with infrared sensors. When infrared emitted from a human body is detected, this sensor goes off. A user should write a program that transmits whether infrared is detected or not to a server.

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Multimedia Communication _ NED University of Engineering & Technology- Department of Electronic Engineering PROCEDURE: 1) Temperature Sensor Control1 In this practice, a user will learn how to read in the temperature of a remote location. A user reads in the surrounding temperature of the location where the temperature sensor is installed. For Temperature Sensor Control1 practice, the following steps need to be followed. Step 1: Mount Temperature Sensor module on to a slave board and turn on the power. Step 2: Run nearby device search of wireless control basic practice. Step 3: Run ACL Connection of wireless control practice Step 4: When ACL connection is made, a message that shows the Temperature Sensor Control1 module connection appears on the bottom of the screen. Then click Temperature Sensor Control1 practice button on the right of the screen. Step 5: When the initial screen appears, the server is ready to receive temperature data transmitted from a slave. Then, the data received from a slave board is displayed on the screen. Once the temperature sensor of the module detects any change in temperature, the color of fan on the screen turns red. A user writes a code that reads in temperature and transmits to a server. Step 6: When the practice is completed, press return button to move to initial screen. The slave side connection is also automatically released. 2) Temperature Sensor Control2 Step 1: Mount Temperature Sensor module on to a slave board and turn on the power. Step 2: Run nearby device search of wireless control basic practice. Step 3: Run ACL Connection of wireless control practice. Step 4: When ACL connection is made, a message that shows the Temperature Sensor Control2 module connection appears on the bottom of the screen. Then click Temperature Sensor Control2 practice button on the right of the screen. Step 5: When sensor detect button located in the center of the screen, the server prepares to receive temperature data transmitted from a client and a slave reads the temperature and transmits to a server. A user will write a program that reads in the temperature and transmits to a server. Step 6: When the practice is completed, press return button to move to initial screen. The slave side connection is also automatically released. Infrared Sensor Control1 Step 1: Mount Infrared Sensor1 module on to a slave board and turn on the power. Step 2: Run nearby device search of wireless control basic practice. Step 3: Run ACL Connection of wireless control practice. Step 4: When ACL connection is made, a message that shows the Infrared Sensor Control1 module connection appears on the bottom of the screen. Then click Infrared Sensor Control1 practice button on the right of the screen.

9

Multimedia Communication _ NED University of Engineering & Technology- Department of Electronic Engineering Step 5: When the sensor detection button on the bottom of screen is clicked, the sensor module receives a signal that notifies the beginning of detection from a server. The sensor notifies a server when detection occurs. Step 6: When the practice is completed, press return button to move to initial screen. The slave side connection is also automatically released. Infrared Sensor Control2 Step 1: Mount Infrared Sensor2 module on to a slave board and turn on the power. Step 2: Run nearby device search of wireless control basic practice. Step 3: Run ACL Connection of wireless control practice Step 4: When ACL connection is made, a message that shows the Infrared Sensor Control2 module connection appears on the bottom of the screen. Then click Infrared Sensor Control2 practice button on the right of the screen. Step 5: In this practice, human body detection sensor is tested. The detected data is transmitted to a server. When a human body is detected, the following screen is displayed. Step 6: When the practice is completed, press return button to move to initial screen. The slave side connection is also automatically released. RESULT:

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LAB SESSION 04

OBJECT:

i. To control Touch Sensor Module using BT devices ii. To control Ultra Sensor Module using BT devices

REQUIRED DEVICES:

Server Hardware Server Program Slave Hardware (PN:BT-3000-1) Controller Module (PN:BT-3000-2) Touch Sensor Control Module (Appl 9, PN:BT-3000-12) Ultrasonic Sensor Control Module (Appl 10, PN:BT-3000-13) PIC Compiler (CCS-C)

THEORY: Touch sensor detect the magnetic energy found in a human body. Once a detection command is transferred, the slave board detects the detection status of a touch sensor and transmits the data to a server. A user should write a program that transfers data to a server. Ultrasonic sensor module detects nearby objects. When an object enters a threshold distance, the sensor goes off. A user writes a program that measures the distance of an object from the sensor and notifies the server. PROCEDURE: Touch Sensor Control Step 1: Mount Touch Sensor Control module on to a slave board and turn on the power. Step 2: Run nearby device search of wireless control basic practice. Step 3: Run ACL Connection of wireless control practice Step 4: When ACL connection is made, a message that shows the Touch Sensor Control module connection appears on the bottom of the screen. Then click Touch Sensor Control practice button on the right of the screen. Step 5: Touch sensor detects a magnetic field of a human body. When sensor operation button on the screen is clicked, the slave board sends the detected data to a server and changes the screen. A user writes a program that notifies a server of the detected situation.

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Multimedia Communication _ NED University of Engineering & Technology- Department of Electronic Engineering Step 6: When the practice is completed, press return button to move to initial screen. The slave side connection is also automatically released. Ultrasonic Sensor Control Step 1: Mount Ultrasonic Sensor Control module on to a slave board and turn on the power. Step 2: Run nearby device search of wireless control basic practice. Step 3: Run ACL Connection of wireless control practice. Step 4: When ACL connection is made, a message that shows the Ultrasonic Sensor Control module connection appears on the bottom of the screen.Then click Ultrasonic Sensor Control practice button on the right of the screen. Step 5: Ultrasonic sensor notifies a server of any detected object within a set distance range. When an object is detected via an ultrasonic sensor, the screen is displayed. Step 6: When the practice is completed, press return button to move to initial screen. The slave side connection is also automatically released. RESULT:

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LAB SESSION 05

OBJECT:

i. To control Gas Sensor Module using BT devices. ii. To control Humidity Sensor Module using BT devices.

iii. To control Pressure Sensor Module using BT devices. REQUIRED DEVICES:

Server Hardware Server Program Slave Hardware (PN:BT-3000-1) Controller Module (PN:BT-3000-2) Gas Sensor Control Module (Appl 11, PN:BT-3000-14) Humidity Sensor Control Module (Appl 12, PN:BT-3000-15) PIC Compiler (CCS-C)

THEORY: Gas sensor measures the concentration of certain gases that are above a set threshold. A user should learn about how a sensor operates and write a program that notifies a server when the sensor detects the gases. Humidity sensor module measures the humidity of surrounding area and notifies it to a server. This sensor is mainly used for humidity adjustment control, however, it is also used to operate other device. A user writes a program that measures humidity and notifies a server. Pressure sensor module detects the difference in pressure when a sensor is pressed and sends the data to a server. A user writes a program that reads in the pressure sensor data and sends to a server. PROCEDURE: Gas Sensor Control Step 1: Mount Gas Sensor Control module on to a slave board and turn on the power. Step 2: Run nearby device search of wireless control basic practice. Step 3: Run ACL Connection of wireless control practice. Step 4: When ACL connection is made, a message that shows the Gas Sensor Control module connection appears on the bottom of the screen. Then click Gas Sensor Control practice button on the right of the screen.

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Multimedia Communication _ NED University of Engineering & Technology- Department of Electronic Engineering Step 5: Gas sensor detects various types of gases in the air and analyzes the concentration of it. The slave board sends the data received from the gas sensor to a server. When gas is detected, the following screen in displayed. Step 6: When the practice is completed, press return button to move to initial screen. The slave side connection is also automatically released Humidity Sensor Control Step 1: Mount Humidity Sensor Control module on to a slave board and turn on the power. Step 2: Run nearby device search of wireless control basic practice. Step 3: Run ACL Connection of wireless control practice. Step 4: When ACL connection is made, a message that shows the Humidity Sensor Control module connection appears on the bottom of the screen. Then click Humidity Sensor Control practice button on the right of the screen. Step 5: In the humidity sensor practice, the surrounding humidity is measured and the data is sent to a server. A user should understand the data transfer method between a server and a slave before programming. When the humidity value is measured and sent to a server, the screen is displayed. Step 6: When the practice is completed, press return button to move to initial screen. The slave side connection is also automatically released. Pressure Sensor Control Step 1: Mount Pressure Sensor Control module on to a slave board and turn on the power. Step 2: Run nearby device search of wireless control basic practice. Step 3: Run ACL Connection of wireless control practice. Step 4: When ACL connection is made, a message that shows the Pressure Sensor Control module connection appears on the bottom of the screen. Then click Pressure Sensor Control practice button on the right of the screen. Step 5: In pressure sensor practice, a user presses the pressure sensor mounted on the pressure sensor module after the sensor detection button of the screen is clicked. The changed pressure value is sent to a server and displayed on the screen. Step 6: When the practice is completed, press return button to move to initial screen. The slave side connection is also automatically released. RESULT:

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LAB SESSION 06

OBJECT: To examine the operation of CD player. EQUIPMENT REQUIRED:

CD trainer M400 Oscilloscope Multimeter Frequency meter

THEORY & OBSERVATION:

1. Insert power plug in a socket powered by supply voltage & check the operation of POWER SUPPLY.

TP1/2 set multimeter to AC & check voltage across secondary winding is 19.5Vac TP3 check there is voltage of 12Vdc which drops down to 10Vdc under load TP4 check there is a stabilized voltage of 5Vdc TP5 check there is stabilized voltage of -10Vdc TP6 check there is stabilized voltage of -27.8Vdc TP7 check there is stabilized voltage of 3.9Vdc

2. Insert power plug in a socket powered by supply voltage & check the operation of

CONTROL, SELECTION & DISPLAY.

TP22 (power ON/standby switch) normally it is powered at 5Vdc & then falls to 0 when button is pressed TP23 (open/close switch) normally it is powered at 5Vdc & then falls to 0 when button is pressed TP30 (standby ckt) it is always powered if plug is inserted TP25 (IR remote control receiver) amplitude of signal is 4V when any key of remote is pressed TP26, 27,28,29(keyboard) a pulse of amplitude of 200mV is generated when any key is pressed

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TP24 (reset) when player is powered through the plug , voltage level passes from 0 to 5 Vdc with a 100ms delay w.r.t. powered line(TP7)

3. Carryout the measurements setting the player to PLAY( MICROPROCESSOR,

DECODER & DIGITAL SERVO INTERFACE).

TP19 this is the reset signal the microcontroller sends to decoder & digital servo to re program new data. Reset is enable when logic state is low (0 Vdc) TP20 this is SDA (serial data) signal through which 2 ckts communicate in bidirectional way for exchanging information. This line in available when logic state is low (0 Vdc) TP21 this is SILD signal that represents control line of load from microprocessor to decoder & digital servo SCL (serial clock signal) operates with previous signal even if there is not any measuring TP


OPENING/ CLOSING OF CD TRAY.

TP18: signal for opening CD tray (tray switch). Normally it is at low logic level (0Vdc) but when it is selected it switches to high level(5Vdc) TP16, 17: control signal of loading/ eject motor. TP16 operates when tray is closed while TP17 operates when tray is opened. The signals are usually at high logic level (2.5Vdc) but they switch to low logic level (0Vdc) for approx 1sec when tray switch is pressed. TP15: control signal of driver for tray motor (loading/ eject motor). Normally it is at 6Vdc


SERVOMECHANISM & MECHANICAL COMPONENTS.

TP9 (laser supply): control signal for switching the laser on (0.7V)off. Normally it is at low logic level(0Vdc) when reading system must not work & it increases to 0.7Vdc in opposite case. TP10, 11(turn table motor): control signal of turn table motor. Signal in TP10 is a pulse with freq of 22kHz & 4Vpp. Signal in TP11 is available only when search keys ( NEXT & PREVIOUS) are pressed.

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TP12 (turn table motor): control signal of driver for turn table motor. It takes direct voltage of 5Vdc (select PLAY) that is reduced when friction opposes the rotation of CD TP13 (sledge motor): control signal of driver for the sledge motor. It takes direct voltage of 5Vdc TP14 (inner switch): stop signal of sledge carrying the pickup. At rest, when switch is OFF, voltage is 0Vdc. When replay starts, switch is on , voltage rises to 4Vdc 6. Insert power plug in a socket powered by supply voltage & check the operation of HF SIGNAL, D/A CONVERSION & AUDIO SECTION

TP8: high freq signal from relay pickup. When the system is not enabled(STOP) it is at low logic level(0Vdc). When replay starts it takes an average value of 2Vdc & amplitude of 2Vpp TP31: word select (WS) for coding right or left from serial data flow. His is a square wave signal with freq 175 kHz & 5Vpp TP32: serial data signal (DATA) including data of right & left channel in alternating sequence TP33: clock bit signal (BCK) of serial data flow. This is a sine wave signal of freq 8.4672MHz & 4Vpp TP34 (audio): reference voltage of 3.3Vdc for operational amplifiers at o/p of both channels TP35: muting signal (KILL) active at low logic level. This disables audio o/p when player is set to PAUSE or it is off. Muting signal is disabled with a high logic value (5Vdc) TP36 (audio): analog signal of left o/p audio channel. If volume increases voltage increases. TP37 (audio): analog signal of right o/p audio channel. If volume increases voltage increases.

RESULT:

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LAB SESSION 07

OBJECT: To examine the fault simulation of CD player. EQUIPMENT REQUIRED:

CD trainer M400 Oscilloscope Multi meter Frequency meter

THEORY & OBSERVATION: There are 16 faults which can be inserted through switches Fault #

1. TP35 normally high 5V, but when fault 1 inserted it is 0V(signal enabling muting/ KILL o/p)

2. TP32 data are available, but when fault 2 inserted data not available any more 3. TP25 normally high 5V, but when fault 3 inserted it is 0V(infra red remote

control is out of service) 4. TP22 normally high 5V, but when fault 4 inserted it is 0V( power on /

standby switch is faulty) 5. TP18 normally high 5V, but when fault 5 inserted it is 0V( tray switch is

faulty) 6. TP13 driving of sledge can be observed in PLAY, when fault 6 inserted ,

sledge motor is faulty(sledge cannot move onwards: listening stops) 7. TP12 driving of central motor can be observed in PLAY, when fault 7

inserted, turntable motor is faulty 8. TP7 normally 3.9V, but when fault 8 inserted it is 0V( zener diode is faulty)

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9. TP36 normally there is an audio signal, but when fault 9 is inserted it is 0V(o/p stage of left channel is faulty)

10. TP34 normally 3.3V, but when fault 10 inserted it is 0V(ckt that generates

reference voltage is faulty) 11. TP29 normally 0V but rises to 0.2V when key is pressed, but when fault 11

inserted it is 0V(keyboard is faulty) 12. TP23 normally 5V,it falls down to 0V when key is pressed for a short time but

when fault 12 inserted it is 0V(tray opening is faulty) 13. TP15 motor driving signal, but when fault 13 inserted correct signal received

(tray motor is faulty) 14. TP7 normally 0V but rises to 4V at start of replay, but when fault 14 inserted

it is 0V(sledge stops where replay ends) 15. TP9 normally 0.7V in play, but when fault 15 inserted it is 0V(laser diode is

faulty) 16. TP6 normally -27.8V, but when fault 16 inserted it is 0V(power supply is

faulty) RESULT:

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LAB SESSION 08

OBJECT: To examine the operation of DVD player. EQUIPMENT REQUIRED:

DVD trainer M500 Oscilloscope Multimeter Frequency meter

THEORY & OBSERVATION:

1. Insert power plug in a socket powered by supply voltage & check the operation of POWER SUPPLY.

TP1 set multimeter to DC & check voltage 5Vdc TP2 set multimeter to DC & check voltage 12Vdc TP3 set multimeter to DC & check voltage 12Vdc TP4 STBY control line (ENABLE / CUT-OFF) of the power supply. When the

equipment is operating, the level of this signal is 0V while when it is on but the key STANDBY-ON has not been pressed the voltage value is +3.2Vdc.

TP5 +5Vstby power supply always on with general switch of the equipment

ON. Voltage of +5Vdc in normal as well as in STANDBY operation. TP6 Power supply voltage of the VDF display: -24V. It is generated directly

form the secondary of the transformer

TP7 Not_ STBY line with logic inverted in respect to STBY. When the signal STBY is not active the value in normal operation of the DVD reader, is +8Vdc When the equipment is in STANDBY, this value is 0V


CONTROL, SELECTION & DISPLAY.

TP8 Enable line of the VFD display circuit. With display ON, cheek the presence of a square-wave of about 0.7V and frequency of about 50KHz.

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TP9 F1 signal of the VFD display. There is a square wave of DC component

having Negative voltage of 20Vdc with modulation at 50khz and amplitude of about 2.5Vpp.

TP10 F2 signal of the VFD display. Square-wave with D.C component of

20Vdc, frequency of 50khz and amplitude of 10Vpp. TP11 Infra-red remote control reception signal converted from IR 7404. The

commands reaching the remote control are detected and transformed into pulses ranging between 0 and +5Vdc.Theduration of each packet of pulses is about 24ms and the composition of pulses on the coded control.

TP12 DATA transmission line between the FRONT DISPLAY BOARD and

the MT1379_216 of the display card. The trains of pulses have a duration of about 100s & 5Vdc.

TP13 CLOCK transmission line between the FRONT DISPLAY BOARD and

the MT1379_216 OF the display card. The trains of pulses have a duration of about 100s & 5Vdc.

TP14 CS communication transmission line between the FRONT DISPLAY

BOARD and the MT1379_216 of the display card. The trains of pulses have a duration of about 100s & 5Vdc.

TP15 Column of the matrix of the OPEN / CLOSE key. This line connects the

input KEY3 of the processor PT6312 with the OPEN /CLOSE key .If no key is pressed and with equipment ON, the measured value in TP15 is +0Vdc. If the OPEN / CLOSE key is pressed, a train of pulses is detected of the duration of 200 ms & +4Vdc. (push previous key)

TP16 Column of the matrix of the STOP key. This line connects the KEY 3

input of the processor PT 6312 with the STOP key. If no key is pressed and with equipment ON , the value measured in TP 16 is +0Vdc. If the stop key is pressed a train of pulses of 200ms duration 5V is detected.

TP17 Column of the matrix of the PAUSE and PLAY key. This line connects

the KEY 4 input of the processor PT 6312 with the PAUSE and PLAY key . If no key is pressed and with equipment ON, the value measured in TP 17 is + 0V dc. If the PAUSE or PLAY key is pressed, a train of pulses of 200ms duration is detected.


DVD LOADING & EJECTION.

TP 18 DVD drawer motor, closing operation ; LOAD +.

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When the drawer is opened with the OPEN / CLOSE push button, the voltage measured in TP18is 0V. When the drawer is closed with the same push button , the signal increases to +4 Vdc for 1.2 s and then returns to OV dc .

TP19 DVD drawer motor, opening operation ; LOAD

When the drawer is closed with the OPEN / CLOSE push button, the voltage measured in TP 19 is OV. When the drawer is opened with the same push button , the signal increases to + 4 V dc for 1.2 s and then returns to OVdc.

TP20 Switch closing when the DVD drawer is closing otherwise it keep open. When the drawer is opened with the OPEN/CLOSE pushbutton, the voltage measured in TP20 is +2.4Vdc. When the drawer is closed with the same pushbutton, the signal returns to 0V.

TP21 STANDBY ON pushbutton.

If the key is not pressed, the voltage on TP21 is +3.3Vdc. If the STAND-BY ON key is pressed the voltage becomes 0V when the key is kept pressed and then returns to +3.3Vdc.

TP22 Central rotation motor DVD SP The measured voltage is +4Vdc during a program execution and so while DVD disk into rotation. With a DVD disk on the reader , the variation of such voltage is analyzed pushing the STANDBYON key , you can check the voltage change when the motor making the DVD rotate is started when still , during the next or last track selection and during the disk stopping with STANDBY ON

TP23 Radial shift motor of the optical pick up

The measured voltage is + 2.6Vdc during a program execution and so with DVD disk into rotation. With a DVD disk on the reader, the variation of such voltage is analyzed pushing the STANDBY-ON key, you can cheek the starting voltage change when DVD rotation is started and during the next or last track selection and during the disk stopping with STANDBY-ON.

TP24 Switch closing when the DVD drawer is open otherwise it keeps closed.

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When the drawer is closed with the OPEN/CLOSE pushbutton, the voltage measured across TP24 is +2.4Vdc while it is 0V when it is opened. When the drawer is closed with the same pushbutton, the signal returns to +2.4Vdc.

TP32 TROPEN LINE. Such line constitutes the command for drawer opening coming from the control logic (MT1336E) and controlled by the integrated circuit BA6208 Which is a specific component for the control of the drawer CLOSE/OPEN motor. When the DVD disk drawer is opened in point TP32, there is a voltage of +2.2Vdc that returns to 0V when the operation is finished and so with drawer opened (using the OPEN/CLOSE close).

TP33 TRCLOSE line. Such line constitutes the command for drawer closing

coming from the control logic (MT1336E) and controlled by the integrated circuit BA6208 which is specific component for the control of the drawer CLOSE/OPEN motor. When the DVD disk drawer is closed in point TP33, there is a voltage of +2.2Vdc that returns 0V when the operation is finished and so with drawer closed (using the OPEN/CLOSE close).


AUDIO/VIDEO card.

TP25 Coaxial outlet line (COAXL). There is a wave-form corresponding to a digital flow of about 1Vpp and variable frequency around 1.5MHz.

TP26 RCA VIDEO outlet line (S_CVBS).

There is a wave form with continuous component of about 1Vdc and a value of about 600 mVpp. (DVD Disk Test, track 02 RED color).

TP27 SCART video outlet line (CVBS). There is a wave form with d.c component of about 1Vdc and a value of

about 600mVpp .(DVD test Disk, track 02 color RED)

TP28 RED video signal (R/V-SCART) of the SCART outlet line. The signal has a value of 300mVpp (DVD Test Disk, track 02 color RED)

TP29 GREEN video signal (G/Y-SCART) OF THE SCART outlet line. The signal has a value of 300 mVpp (DVD Test Disk, track 03 color

GREEN):

TP30 BLUE video signal (B/U-SCART) of the SCART output line.

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The signal has a value of 300 mVpp (dvd Test Disk, track 04 color BULE):

TP31 Left channel audio signal LOUT+.

The signal is sine shape and has a d.c. component of about 1.2Vd.c and 1.3Vpp (DVD Test Disk, track 06, 1 KHz left)

TP34 Video signal Y3.

The signal has a value of 800mVpp (DVD Test Disk, track 01, colors spectrum).

TP35 Left channel audio signal of the SCART socket (SCART-L).

The signal has no d.c. component and a value of 4Vpp (DVD Test Disk, track 06, 1KHz left).

TP36 Right channel audio of the SCART socket (SCART-R).

The signal has no d.c. component and a value of 4Vpp (DVD Test Disk, track 08, 1 KHz right).

TP37 SCART socket FBOUT line.

If a SCART socket is inserted into the rear connector of the equipment, in TP37 there is a voltage of +2.5Vdc or 0V on the contrary.

TP38 MUTE audio command line (A_MUTE).

The voltage measurement in point TP38 is +2Vdc with MUTE function inserted (with track forward moved by the remote control) and 4Vdc normally with audio and video.

TP39 Left channel audio signal of the RCA socket (LCH).

The signal has no d.c. component and a value of 5Vpp (DVD Test Disk, track 06, 1 KHz left).

TP40 Right channel audio signal of the RCA socket (RCH).

The signal has no d.c. component and a value of 5Vpp (DVD Test Disk, track 08, 1KHz right).

RESULT:

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LAB SESSION 09

OBJECT: To examine the fault simulation of DVD player. EQUIPMENT REQUIRED:

DVD trainer M500 Oscilloscope Multi meter Frequency meter

THEORY & OBSERVATION: There are 18 faults which can be inserted through switches Fault 18 With the fault 18 inserted, the measured voltage at TP2 is 0Vdc, the

PAUSE PLAY and STOP commands are cut-off and the audio is not reproduced.

Fault17 With fault 17 inserted, the measured voltage at TP5 is 1.5Vdc, the remote

control does not operate.

Fault 16 With fault 16 inserted, the measured voltage at TP11 is 0Vdc and the remote control does not operate.

Fault 15 With fault 15 inserted, the voltage measured at TP20 is 0Vdc, the DVD

drawer dose not open. Pushing the OPEN/CLOSE key, the drawer opens but it cannot be closed anymore.

Fault 14 With fault 14 inserted, the voltage measured at TP21 is 0Vdc, the

STAND-BY On key dose not operate. Fault 13 With fault 13 inserted, the voltage measured at TP27 is 0Vdc, the video

output voltage is not present on the SCART connector. Fault 12 With fault 12 inserted, the voltage measured at TP29 is 0Vdc, the video

output voltage related to the GREEN color is not present on the SCART connector.

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Multimedia Communication _ NED University of Engineering & Technology- Department of Electronic Engineering Fault 11 With fault 11 inserted, the voltage measured at TP7 is 0Vdc, the DVD

rotation progressively stop and the equipment goes in STANDBY. Fault 10 With fault 10 inserted, the voltage measured at TP40 is 0Vdc, the audio

related to the RIGHT channel is not reproduced. Fault 9 With fault 9 inserted, the measured voltage at TP8 is 0Vdc and the VFD

display of the equipment switches off although the DVD program operation and the PAUSE, PLAY, STOP keys and the remote control keep operating.

Fault 8 With fault 8 inserted, the measured voltage at TP15 is 0Vdc, the OPEN /

CLOSE key does not operate Fault 7 With fault 7 inserted, the measured voltage at TP18 is 0Vdc, the DVD

drawer does not open. Pushing the OPEN / CLOSE key, the drawer does not open and after 5 seconds the measured value becomes + 5V dc.

Fault 6 With fault 6 inserted, the measured voltage at TP22 progressively ranges

between 4Vdc and 0Vdc with a gradual slowing down of the DVD disk rotation until it stops.

Fault 5 With fault 5 inserted, the voltage measured at TP26 is 0Vdc, the video

output voltage is not present on the RCA connector.

Fault 4 With fault 4 inserted, the voltage measured at TP28 is 0Vdc, the video output voltage related to the RED color is not present on the SCART connector.

Fault 3 With fault 3 inserted, the voltage measured at TP30 is 0Vdc, the video

output voltage related to the BLUE color is not present on the SCART connector.

Fault 2 With the Fault 2 inserted, the voltage measured is +2Vdc, the audio is not

reproduced. Fault 1 With fault 1 inserted, the voltage measured at TP38 is 0Vdc, the audio

related to the LEFT channel is not reproduced.

RESULT:

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LAB SESSION 10

OBJECT: To check the operation of VTR (Video Tape Recorder)

i. Troubleshooting on the supply and take up reel sensors circuit. ii. Troubleshooting on the drum motor circuit

EQUIPMENTS REQUIRED:

VCR trainer EAV-VCT-M3 Color Television. Digital multimeter

THEORY: The reel spindle rotate to supply reel and take-up tape as it travels through the tape transport mechanism. The supply reel and take-up reel have sensors. Each sensors detect the spindle when is turning. The sensor regulates the tape & hold back according to how much tape is on the supply reel and take-up reel. The drum servo system has two control loops called speed servo loop and phase servo loop. The speed servo loop controls the drum rotation to be precisely 29.97 rps. For 60 Hz system, which is for the frame frequency in color television. The phase servo loop controls the phase, or timing to make sure that one of the two video heads, called the reference head, crosses the spot on the track where vertical sync is to be recorded at the precise instant it occurs in the video signal. PROCEDURE: ( REEL SENSOR):

1. Prepare the VCR trainer and other equipment. 2. Connect Ribbon cable from VCR to Fault panel. 3. Use the Video/Audio cable (RCA cable). Connect it into Video/Audio line out of

VCR and into the Video/Audio line input of the color TV. 4. Operate VCR trainer and color TV monitor by pressing power buttons. 5. Set TV to receive VCR signal. 6. Insert video cassette into VCR. 7. Measure the TAKE-UP REEL sensor signal at TP16 and then record the result. 8. Activate the TAKE UP REEL sensor fault simulator by pressing the fault button

on block diagram panel.

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9. Press FF button to forward the cassette. Observe the forwarding process on VCR. Did the forwarding process operate correctly? ---------------------------------------------------------------------------------------------------

10. Measure again the take up sensor signal at TP16, compare the result to step 7 above.

11. Reset the fault simulator. 12. Activate the SUPPLY REEL sensor by pressing the fault button, the indicator

fault will lit. 13. Press REW button to rewind the cassette. Observe the rewinding process on VCR.

Did the rewinding process work correctly? ---------------------------------------------------------------------------------------------------

14. Reset the fault simulator. 15. Eject the video cassette. 16. Turn off the VCR trainer and TV monitor.

(DRUM MOTOR):

1. Prepare the VCR Trainer and other equipment. 2. Connect Ribbon cable from VCR to Fault Panel. 3. Use the video/Audio cable (RCA cable). Connect it into video/ Audio line input

of the color TV. 4. Operate VCR trainer and Color TV monitor by Pressing power buttons. 5. Set TV to receive VCR signal. 6. Insert video cassette into VCR. 7. Press PLAY button to playback process. 8. Measure the Drum FG signal at TP 12. Observe the waveform and record. 9. Activate the drum FG fault simulator by pressing the fault button. Observe the

playback process on mechanic system of VCR. Did the drum motor stop?

Did the playback process still run?

10. Measure again the Drum FG at TP12. Compare the result to step 8 above 11. Press RESET button to normal function. 12. Run the recording process and then activate the Drum FG fault simulator again. 13. Observe the fault effect on mechanic system. 14. Press RESET button to normal function. 15. Write down the fault effect of the Drum FG circuit malfunction at the time

playback process and at the time recording process. ___________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________ 16. Eject the video cassette. 17. Turn off the VCR trainer and TV monitor.

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Multimedia Communication _ NED University of Engineering & Technology- Department of Electronic Engineering RESULT:

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LAB SESSION 11

OBJECT: To become familiar with the use of 4 telephones connected to the local switching centre. THEORY: Local Signalling: The signalling between the telephone user, and the local Switching Centre is known as local signalling. The signals available to the user are the Switch Hook and the Keypad. The Switch Hook operates as soon as the telephone is lifted. This is the Off Hook state of the telephone, and is recognised by the Switching Centre. The Keypad is primarily used to send the Destination Address to the Switching Centre; that is the number of the telephone to which the connection is required. Dual Tone Multi-Frequency (DTMF) signalling: The signals are in the form of a combination of two audible tones, a different combination for each number on the Keypad. Hence it is known as Dual Tone Multi-Frequency (DTMF) signalling. The Switching Centre can send signals to the user, by using tones and by ringing the bell or alerter in the telephone. The audible tones are known as call progress tones, and indicate to the user important responses of the Switching Centre. Obviously they are only useful if the user is listening to the telephone. If the telephone is not in use, i.e. if it is on hook, then the Switching Centre can ring it. ITU-T Standards: Standards for the telephone industry are agreed by an international body. Up to 1994 it had a French name, Comite Consultatif International de Telegraphique et Telephonique (CCITT). Since then it has been known as the Telecommunications Standardisation Sector of the International Telecommunications Union (ITU-T).The ITU-T produced a Standard Recommendation E.180 for the tones used in local signalling. Each telephone system is run by an Administration, sometimes a public Administration, usually running the whole telephone system in one country, and sometimes privately owned. Historically each Administration has often used different tones for the same purpose. The ITU-T Recommendation aims to reduce these differences so that in international calls operators and users understand easily the meaning of the tones. The Recommendation includes 'acceptable' tones for each purpose, and 'recommended' tones for new systems. The general nature of each tone, and the acceptable and recommended limits are: Dial Tone: Dial Tone should be a continuous tone, either a single frequency in the range 400-450 Hz, with 425 Hz preferred, or a combined tone of up to 3 frequencies, with at least one frequency in the ranges 340-425 and 400-450 Hz, with at least 25 Hz difference

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Multimedia Communication _ NED University of Engineering & Technology- Department of Electronic Engineering between any 2 frequencies. However any existing dial tones, including interrupted tones are acceptable, because of the technical and social difficulties of changes. Ring Tone: Ring tone is a slow period tone, in which the tone period is shorter than the silent period. The recommended limits are 0.67 to 1.5 seconds for the tone and 3 to 5 seconds for the silence; and the acceptable limits are up to 2.5 sec and up to 6 seconds respectively. The recommended frequency is 400-450 Hz, with 425 Hz preferred; and the acceptable range is 340-500 Hz. Busy Tone: Busy tone is a quick period tone, with the tone and silence periods equal. The total duration of both tones is recommended to be 0.3 to 1.1 seconds; and the ratio of tone to silent period should be between 0.67 and 1.5. The recommended frequency is 400-450 Hz, with 425 Hz preferred; and the acceptable range is 340-500 Hz. Number Unobtainable Tone: No recommendations are made. System Operation: The normal use of the 4 telephones connected to the local Switching Centre is demonstrated in this Practical. By using the telephones to make calls, the basic operation of the Switching Centre is examined. The telephones use single digit numbers. The numbers to be dialed correspond to the Line numbers L1 to L4 shown on the Work board i.e. 1, 2, 3 and 4. The system uses 4 Call Progress Tones: Dial tone, Ring tone, Busy tone and Number Unobtainable (NU tone). Using the telephones the tones can be heard. Also the connection of them can be seen on the Switching Centre diagram. Ringing the telephone requires a much larger voltage than the acoustic Tones. This is indicated by a different colour inside the Switching Centre diagram. The Digital Switching Centre Work boards used for this can operate as one of two types, A or B. The work board used for the single Switch Assignments, must be set to type A, by the Switching Centre Type switch at the far right hand corner of the board. If two boards are connected, the other should be type B, and is not used for these Assignments. PROCEDURE & RESULT:

1. This exercise is to become familiar with the use of the 4 telephones connected to the local switching centre. The numbers for the telephones for the first Assignments correspond to the line numbers on the work board, i.e. 1 to 4.

2. The work board must be set to Type A. If there is another board connected, it must be type B, and is not used. The tones are preset but non-standard.

3. Put all 4 telephones face down (On Hook). 4. Pick up telephone 1. Dial Tone is heard, and the connection is shown on the

diagram. Press button 2. Ring Tone and Alerting (Ring) are applied to telephones 1 and 2. Pick up telephone 2. Speak into one of them to check the connection.

5. While the first connection is held, pick up telephone 3 and press button 1. Busy Tone is heard. Then replace telephone 3.

6. Replace telephone 2. Is the connection broken? Replace telephone 1.

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7. Using any telephone, listen to Dial Tone, and then press button 8. Number Unavailable Tone (NU Tone) is heard.

8. Try out other connections.

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LAB SESSION 12

OBJECT: To become familiar with time switching & space switching. THEORY: Digital Transmission: Digital telephone signals use a synchronous transmission system, which combines Time Division Multiplexing (TDM) and Pulse Code Modulation (PCM). Each speech path has to send an 8 bit binary code at a rate of 8000 codes per second. The codes are organized into groups called frames. Each code is transmitted in a timeslot. The frames include special synchronizing codes so that each timeslot can be identified and the code correctly converted back to analogue form. In the CEPT system which originated in Europe there are 32 timeslots in each frame. Each frame takes 125 s, and each 8 bit timeslot is transmitted in 3.9 s, at a rate of 2.048 Mbps. In the T1 system which was designed in North America there are 24 timeslots in each frame. Each frame also takes 125 s, and so each 8 bit timeslot is transmitted in 5.2 s. An extra bit is used for synchronizing so the transmission rate is 1.544 Mbps. The connection to each telephone uses 2 wires which carry analogue signals in both directions. For Digital Switching, incoming and outgoing speech are separated by hybrid circuits. Then combined Codec/Filter circuits provide analogue to digital and digital to analogue conversion. Speech Paths:

The Codec/Filter circuits are connected to the Digital switch through Inlet and Outlet Busses. Each Bus can carry up to 24 or 30 speech connections, depending on the PCM system in use. Each Codec is connected to the Inlet and Outlet Busses at a designated time; for the period of one timeslot.

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Multimedia Communication _ NED University of Engineering & Technology- Department of Electronic Engineering Basic Digital Switching: The Digital Switch transfers the contents of each timeslot in the Inlet Bus to the appropriate timeslot in the Outlet Bus. Switching of the data from each timeslot in the Inlet Bus requires changing the time at which the data is transmitted along the Outlet Bus. The process is known as Time Switching or Time Slot Interchange. Time and Space Switching: Most switching systems have more than 24 or 30 channels and use more timeslots than can be accommodated in one Bus. Therefore switching between the Busses is required. The Digital Switch shown must switch between different timeslots and also between different busses.

Time Switching: The basic process in Digital Switching for telephone systems is the transfer of 8 bits of digital data from one Timeslot to another. The speech signals from each telephone are connected through a Codec to the Switch during a specified Timeslot. The connections are made along Inlet and Outlet serial busses. The simplest connection between 2 telephones occurs if they are both using the same Inlet and Outlet busses. They must, of course, use different Timeslots. Then 8000 times per second the contents of the Inlet Timeslots for each telephone must be transferred to the Outlet Timeslots of the other. This is Timeslot Interchange or Time Switching. The Timeslots are organized in Frames. Each Frame has 32 (CEPT systems) or 24 (T1 systems) Timeslots. Successive Frames are transmitted along the same physical connections i.e. the same Inlet and Outlet busses. The data for transmission is only available briefly, and the display flashes to suggest this. Of course the actual data transmission is very much faster than the flashing. For convenience one digit dialing is still used in this Assignment (Line numbers 1 to 4). Time and Space Switching: One 30 channel CEPT serial bus can accommodate 30 telephones, and each T1 serial bus can accommodate 24 telephones. Hence any larger system requires more Inlet and Outlet serial busses, particularly if they are public systems. Hence switching between serial busses is required as well as time switching. This is known as combined Time and Space Switching.

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Multimedia Communication _ NED University of Engineering & Technology- Department of Electronic Engineering The demonstration uses two Inlet and two Outlet serial busses. In a large system there are many such serial busses, and complex combinations of Time and Space switching are used. PROCEDURE & RESULT: Preliminary Procedure:

Check the Workstation set up as follows:

One Digital Switch Centre If there is only one Digital Switch Centre and Telephone Tray (58-122 and 58-123) connected to the system controller 58-121, make sure the Switching Centre Type Switch is set to 'A' (green LED on).

Two Digital Switch Centres If there are two Digital Switch Centres and

Telephone Trays (58-122 and 58-123), one Switching Centre Type Switch should be set to A (green LED on) and the other to B (yellow LED on). A curly trunk cable should interconnect the Trunks connectors. Use Switch Centre 'A' for the Practical.

Two Digital Switch Centres plus a Trunk Networks Board With two Digital Switch Centres and Telephone Trays (58-122 and 58-123) and a Trunk Networks Board, 58-140 included in the set-up, one Switching Centre Type Switch should be set to A (green LED on) and the other to B (yellow LED on). Curly trunk cables should interconnect the Trunks connectors. Use Switching Centre 'A' for the Practical.

Procedure for Time Switching:

1. Switching between 4 telephones, all of them connected to one bus. The data is only available briefly in each timeslot, as suggested by the flickering display.

2. Make a connection between any two telephones. They have numbers 1 to 4. Observe which timeslots have their contents exchanged to carry the speech signal from one telephone to the other.

3. Make another connection without breaking the first one and observe the new timeslot interchange.

4. Clear the connections and make new connections. Procedure for Time & space switching:

1. The 4 telephones are now connected to 2 timeslots in different busses. 2. Again make different connections between the telephones. They are numbered 1

to 4. 3. In each case observe the timeslot interchanges required. Some of them are in the

corresponding serial bus, for example from Inlet bus 0 to Outlet bus 0 but some require speech data to be exchanged into an unrelated bus.

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LAB SESSION 13

OBJECT:

i. Determined the relationship between information held within the control memory and the actual switching operation.

ii. Established the procedure to connect tones to calling lines. THEORY: Digital Switch Architecture: The Switch has an Inlet Buffer (Serial In and Parallel Out), and an Outlet Buffer (Parallel In and Serial Out) for each Serial Bus connected. The Buffers and the Data Memory are connected internally by a parallel bus, which can operate much faster than the serial busses. The Connection Memory is used to control the time at which the contents of each timeslot are sent to the Outlet Buffer.

Switch Operation: The incoming serial data along one Inlet Bus enters the Inlet Buffer. The data in each timeslot is read into a location in the Data Memory in sequence as it arrives. Thus the position in the Data Memory indicates which timeslot was connected.

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Multimedia Communication _ NED University of Engineering & Technology- Department of Electronic Engineering To achieve Time Switching, the data from each location in the Data Memory must be read at the correct time, and sent to the Outlet Buffer. Each location in the Connection Memory is used for the same timeslot as the corresponding location in the Data Memory. However each Connection Memory location contains an address, not data. The address is that of the Data Memory location which should be read and the data sent to the Outlet Buffer for each timeslot. Thus by writing data into the Data Memory sequentially, but reading it when required, Time Switching is obtained. Combined Time and Space switching is obtained using the same principle. More Inlet and Outlet Buffers are used for the additional busses, all connected by the parallel bus to the Data Memory, which is more extensive. A limit on switch capacity is reached when the internal bus cannot reach the speed required for transfer of all the data. In that case combinations of switches are used. Control of Time Switch: Switching using RAM The method used for Time Switching is to write the 8 bits of data in each Timeslot into a location in a random access memory (RAM). Then at the correct time the data is read from the RAM and transmitted through the Switch Outlet. To do this the Digital Switch writes the data from each Timeslot in the Inlet serial Bus into the Data memory. Each location in the Data Memory corresponds to a particular Timeslot in the Inlet Serial Bus. The data is read out from the Data Memory and sent to the Outlet Serial Bus in the correct sequence for the particular connection required. Switch Control: The output sequence is controlled by the Connection Memory. Each location in the Connection Memory also corresponds to a Timeslot in the Outlet Serial Bus. The Connection Memory contains the addresses of the Data Memory from which each Timeslot data can be read. The addresses are inserted when the connection is set up. At the time for the data to be transferred to the Outlet, the address is read in the corresponding location in the Connection Memory, and used to find the data in the Data Memory.

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Multimedia Communication _ NED University of Engineering & Technology- Department of Electronic Engineering The data is held for a complete Frame; ie, 125 s, in the Data Memory before being written over by the data from the next corresponding Timeslot. This is indicated by the display not flashing as quickly as the serial data. Connection of Tones: The Digital Switch is used to connect each of the 4 tones used for signalling to the telephone user. The tones are Dial tone (DT), Ringing tone (RT), Busy tone, and Number Unobtainable (NU tone). The tones are continuously available in particular timeslots, and are connected to each line as required. Each tone can be connected to as many telephones as necessary simultaneously. Each tone can be programmed (see the Local Signalling Assignment). Whether it is the programmed or preset tones that are used, they are available in the same timeslots. Procedure: Preliminary Procedure: Check the Workstation set up as follows:





Procedure for Control of Time Switch:

1. Make a connection between any two telephones. 2. Observe the addresses written into the Connection Memory. These tell the system

where in the Data Memory to find the data for the output timeslot.

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Procedure for Connection of Tones: The 4 tones for signalling to the telephone are available in specified timeslots, in one serial bus. They are connected as required to the telephone timeslots, again under the control of the connection memory.

1. Pick up one telephone and listen to the dial tone. Dial another telephone, see that

dial tone stops, and then ring tone starts. Answer the telephone. 2. Then try to connect a third telephone to one of the first two. Finally try to connect

to an invalid number.

39


LAB SESSION 14

OBJECT: To learn how the call state, call record, call progress are made. THEORY: Call Records: A Call Record is an area of memory in which the essential data for any call is held. Each time a telephone goes off hook in order to start a call, a new Call Record is opened. The essential items are: The call state, which indicates the position which a call has reached in the sequence of events.

The identity of the calling line The identity of the required line The duration of the call The timing of the Ring Count.

These items, together with the Line Scan inputs, are the total requirements for the Control microprocessor to handle the call. The Call Records are numbered R1 to R4. For a very small system it is possible for all telephones to be Off Hook together and so there has to be a Call Record for each one. However you will probably notice as you work with the system that it is unusual for all 4 to be needed. In large systems an assumption is made that most telephones are not in use most of the time, and so only a small proportion of possible connections are ever made Call States and Transitions:

The first Practical uses this diagram to illustrate the progress of a Call through various Call States. The diagram is the basis of a 'Process' diagram as defined in the ITU-T Specification and Description Language (SDL). It serves as an introduction to the SDL concepts.

40

Multimedia Communication _ NED University of Engineering & Technology- Department of Electronic Engineering Call State: The concept of Call State is the method for organizing the control of the telephone system. The Call States in this system are numbered S0 (Idle) to S7 (Speech). The progress of a call is monitored by reference to its State. Most of the time of the Control in the Switching Centre is spent waiting for the next input from a user. When the Line Scan detects a change of Input from the Hook Switch, or from the DTMF Receivers, it refers to the Call State, if any, for that Line to determine the significance of the Input. Dialing: In this 2 digit dialing is used. This is more realistic, and enables the Call Processing to be more clearly observed. The preset numbers for the 4 Lines are 21, 22, 31 and 32, respectively. State S3: Note that local calls, in the single Switch used for this Assignment, do not need to dwell in State S3 - Find Line. This is because the processor can determine immediately whether the required line is free, busy or unobtainable, and is an internal transition. A short pause at State S3 is imposed, but would not normally be used. State S3 is examined more closely in other Assignments. As an example, consider the system starting in State S0, Idle. When the Line Scan shows an unused handset off-hook, it responds with dial tone. A Transition is made to State S1 - Call Request. As the call progresses more Transitions occur. At any point, if the call is released, then the system reverts to State S0 - Idle. The Call State is recorded at each stage in the Call Record. Use of Call State Transition Diagram: The advantages of the Call State Transition Diagram include:

It provides an exact specification of the operation of the system and at the same time it enforces a discipline on the system designer.

The control software is designed and tested by considering the possible States. The complexity of a large system is thus reduced to a number of simple steps.

For design if a system is in a particular State, only certain Transitions are possible, and only those need to be provided. For testing, from any State it is only required to ensure that the required Transitions, and only those, occur. Line Identities: For the Call Record the lines are identified by their Equipment Numbers, which correspond to the Telephone Line numbers L1 to L4 on the Work board. There are 2 Line Identities used in the Call Record. The Calling Line Identity CLI is entered when the Call Record is opened. The Required Line Identity RLI is entered when it is identified by the dialed numbers. Call Progress: The basic information required by the Control to process a call comprises the Call State CS and the Line Identities CLI and RLI. With that information, incoming signals from the telephone are correctly interpreted. All switching whether of Tones or Ringing or final Connection can be performed. Release of a call may happen at any State of the call. Hence correct disconnection also requires all the 3 items, CS, CLI and RLI.

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Multimedia Communication _ NED University of Engineering & Technology- Department of Electronic Engineering Call Duration: The duration of any telephone call is important to a telephone company for various reasons. The main reason is for charging the user for the call. When the call is completed, the details of the call are recorded and used for calculating the bill. Also it is useful to keep some statistics on the system performance. For example the time required to set up a call, for which the company is not paid, affects the amount of computing equipment needed by the system. Finally if calls are not completely established, e.g. a phone is left off-hook without dialing, after a certain period it may be disconnected or an alarm message may be sent. Ring Count: According to the ITU-T recommendation, Ring Tone and the Ringing signal should commence as soon as the connection is made. To achieve this without distorting the normal Ring cadence, the Tone period must start immediately. Hence the cadences for each line are not synchronous, and must be counted independently. The unit of time for the Ring Count is 0.1 second. It is convenient to provide a location for the count with the Call Record. However no further use is made of the data. PROCEDURE & RESULT: Preliminary Procedure: Check the Workstation set up as follows:





Procedure for Call state:

1. The Call State is used by the control to determine the progress of any call. The active Call State Transition Diagram shows the possible Transitions between States.

2. 2 digit dialing is now needed to demonstrate reasonable call progress. The lines L1 to L4 have preset numbers 21, 22, 31, 32. These can be changed in the Line Records, Numbering Practical.

3. Lift just one telephone and go through the stages of a call.

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4. The Call State table shows which State each Call Record has reached. The related Call State Transition Diagram (CSTD) shows the progress of any call. If necessary use the Select Record button to find the current CSTD.

5. Make two calls simultaneously and follow their progress on the 2 CSTDs. Try to connect to a telephone already in use; and to a nonexistent directory number.

Procedure for Call progress:

1. There are 2 Line Identities required for the Call Record. The Calling Line Identity CLI is entered into the Call Record when a new Record is started.

2. The Dialed Number is stored as the digits are dialed. When it is complete, if the required line is not Busy or Unobtainable, the Required Line Identity RLI is entered into the Call Record.

3. Use the telephones to make various connections (2 digit dialing). Observe when the Identities are entered and removed from the Call Records.

Procedure for Call duration:

1. The duration of each call, in seconds, is maintained in each Call Record. Timing starts as soon as the Call Record is opened.

2. When a connection is made, the Set Up duration is recorded for the Traffic statistics. The Call Duration is then restarted.

3. The control of Ringing also needs a location for counting the course of the Ringing cadence. The Ring Count is counted in units of 0.1 second.

4. Make some connections (2 digit dialing), and observe the timing.

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LAB SESSION 15

OBJECT: To learn about Call Progress Assignment. THEORY: This shows the complete system records for actual successful or unsuccessful calls. The Call Progress Practicals are:

Call Set Up Call Supervision Call Release

Call Progress: In large telephone systems the computer system must be able to deal with many different calls, at different stages as each call progresses. It is convenient to divide the control into different phases, each dealing with a particular aspect of the call.

A common system is to divide the control into 3 phases: Call Set Up: This includes all the initia

MMC (TC) Lab Manual 2009

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