ARM based Multimedia IP Phone is a telephone with ARM processor, capable of sending and receiving real time data signals over the existing data network. It uses LPC1788 microcontroller to implement the standard data communication protocols using lwIP - open source library and modern touch based user interface using emWin Graphics library. The project also features a battery powered Uninterruptible Power System (UPS) for increased portability and standalone ability. Further, to demonstrate the use of IP telephony and VoIP, client server based computer applications are also developed.

1. ARM based
Multimedia IP Phone
THAPATHALI CAMPUS
FINAL PRESENTATION
MEMBERS
Bijay Raj Paudel (Roll No: 067/BEX/105)
Kshitij Poudel (Roll No: 067/BEX/119)
Sagar Mali (Roll No: 067/BEX/133)
Sujan Shrestha (Roll No: 067/BEX/140)
SUPERVISOR
Bikash Poudel

2. 1. INTRODUCTION
 IP based Telephone System
 IP Phone powered by ARM processor
 Implements VoIP technology
 UPS System for standalone operation
2

3. 2. OBJECTIVES
 To design and implement Multimedia capable IP
Telephone using ARM processor
 To demonstrate the implementation of IP telephony
system in LAN using developed ARM based IP phone as a
client
3

4. 3. PROJECT OVERVIEW
4

5. 4. METHODOLOGY
4.1 Hardware
4.2.1 UPS System
4.2.2 Battery Status Display and Temperature Sensor
4.2.3 Main Phone Unit
4.2 Firmware
4.3.1 Networking Protocols
4.3.2 User Interface for ARM
4.3.3 IP Phone Firmware
4.3.4 Software for PC
4.3.5 Audio Codecs and Playback
5

6. 4.1 Hardware
4.2.1 UPS System
4.2.2 Battery Status Display Unit
4.2.3 Main Phone Unit (ARM Development Board)
6

7. 4.2.1 UPS System
 For the operation of IP phone during power outrage
7

8. 4.2.1 UPS System
FEATURES
 Switches between main supply and battery
 Standard CCCV charging algorithm
 Overcharge Protection
 Deep Discharge Protection
 Regulated 5 V Supply
8

9. 4.2.2 Battery Status Display and
Temperature Sensor
 Receives Voltage and Current level from battery
 Receives Temperature Status from LM35
 Uses ATmega8 for ADC
 Transfers data via USART and RS232 interface
9

10. 4.2.2 Battery Status Display and
Temperature Sensor
Block Diagram
10
TEMP. 2
RS232
INTERFACE
ATmega8
BATTERY
LM35
VOLTAGE
CURRENT
TEMP. 1

11. 4.2.3 Main Phone Unit
11
 Implemented on EM-LPC1788 development board based
on the main chip LPC1788 produced by NXP
 Has ARM Cortex M3 microcontroller LPC1788

12. 4.2.3 Main Phone Unit
12

13. 4.2 Firmware
4.3.1 Network Protocols
4.3.2 User Interface for ARM
4.3.3 IP Phone Firmware
4.3.4 Software for PC
4.3.5 Audio Codecs and Playback
13

14. 4.3.1 Network Protocols
 TCP/IP (Transmission Control Protocol/ Internet Protocol)
 DHCP (Dynamic Host Control Protocol)
 ICMP (Internet Control Messaging Protocol)
 TCP/IP used instead of UDP for real time audio data
14

15. 15
lwIP Protocol Stack

16. 4.3.3 IP Phone Firmware
16
IP Packet Stack
 Defines a standardized packet format for
delivering audio and video over IP networks
 Uses TCP for packet transfer
Text and other
Data
Audio Codec RTCP Call Signaling Multimedia Control
RTP Signaling
TCP
IP

17. 4.3.2 User Interface for ARM
 User friendly interface
 TFT LCD (480x272) and
 4-wire touch
 Implemented using emWin Graphics Library
17

18. 4.3.4 SOFTWARE FOR PC
 To send, receive and monitor
call from PC
 Server
 Addressing
 Client control
 Client
 Developed using C# language
based on .NET framework
 User interface using Windows
Presentation Foundation (WPF)
 Limited only to windows
18

19. 4.3.5 Audio Codecs and Playback
 Microphone Input
 Speaker Output
 ADC, DAC
 Sampling, coding, decoding
 UDA1380 one chip solution
 I2S data
 I2C control
23

20. 4.3.5 Audio Codecs and Playback
20
Recording Block Diagram

21. Control
register
Values
4.3.5 Audio Codecs and Playback
21
Playback Block Diagram
Data Input
Interface
DSP features
Interpolation
Filter
I2C Bus Interface
Noise
Shaper
FSDAC
Headphone Driver

22. THE SOFTWARE FLOW
 The one-way software flow on both sender and
receiver
Data Encode Audio encode
RTP Stack
Output device
Audio decode
Digital A/V signal in
IP Packet
Data Decode
Signaling Stack
Ethernet
Digital A/V signal out
Unpack
IP Packet
User
interface
User
interface
24
Ambient and
Battery
Temperature,
Battery level

23. 6. APPLICATIONS
 Private Network Communication System
 Education and Classroom
 Telemedicine and treatment
23

24. 7. LIMITATIONS
 Lack of separate video hardware so video communication
was a big challenge and had to be abandoned
 Camera
 Decoder Encoder
 Clock Limitation
 Lack of Operating System was a problem for scheduling
as everything had to be interrupt driven
24

25. 9. FUTURE ENHANCEMENT
25
 Video communication
 Multi-platform based software
 Encryption for security purpose
 SMPS based power supply

26. REFERENCES
Books
 Tanenbaum, A. S. & Wetherall, D. J. (2011). Computer Networks
 Viswanathan, T (2012). Telecommunication Switching Systems and NetworkS
 Haykin, S (2013). Digital Communication Systems.
 Sloss, A & Symes, D & Wright, C (2004). ARM System Developer's Guide.
Websites
 Wikepedia. (2014). Voice over IP. Available: http://en.wikipedia.org/wiki/Voice_over_IP.
Last accessed 20th Feb 2014.
 Valdes,R & Roos,D. (2014). How VoIP Works. Available:
http://computer.howstuffworks.com/ip-telephony.htm. Last accessed 18th Feb 2014
Documents
 Sadasivan, S .(November 2010). Developing optimized signal processing software on the
Cortex‐M4 processor. Retrieved February 10,2014, from
http://www.arm.com/files/downloads/Developing_Advanced_Signal_Processing_Softwar
e_on_the_Cortex-M4_Processor.pdf.
 Ward, M .(Number 4, 2005). Developing Video Phones with ARM Processor -based
Solutions. Retrieved February 10, 2014, from
http://www.iqmagazineonline.com/magazine/pdf/v_4_4_pdf/v_4_4_pg-16-19.pdf
26

27. THANK YOU!