This document discusses internet telephony and voice over internet protocol (VoIP). It describes the minimum requirements to use internet telephony including a PC, sound card, speakers, and internet connection. It explains how VoIP works by converting analog voice signals to digital data. There are three main types of internet telephony: analog telephone adaptor, IP phones, and PC-to-PC. Internet telephony offers lower costs for domestic and international calls compared to traditional phone services. While it provides benefits like reduced costs, security and reliability issues still exist.

2. Introduction
Internet telephony is a powerful and
economical communication option by
combination of the telephone network and data
networks.
Internet telephony uses internet to send audio
between two or more computer users in the real
time , so the user can converse vocal Tec
introduced the first internet telephony software
product in early 1995

3. Minimum Requirements
A Pentium processor based PC
Microsoft Windows 95 or newer operating
system
A properly configured sound card
A pair of speakers and a microphone
A stable internet connection (at least 28.8
kbps)
TCP/IP connectivity

4. Internet Protocols
 IP packets are forwarded across the network by
routers
 IP Routers do best-effort routing
Voice signals can be prioritized using priority queues
 RTP and RTCP keep end points informed of
transmission quality.
 Call set up is done using Session Initiation Protocol
(SIP) or something similar

5. How it works
 Voice over internet protocol (VOIP)
turns analog voice signals to digital
data.
 Lower costs – Domestic &
International
 Three types of internet telephony
◦ ATA
◦ IP Phones
◦ PC to PC

6. ATA
Most common method
Analog Telephone Adaptor (ATA) is an
analog to digital converter
Enables you to connect a standard
phone to a computer or Internet
connection

7. IP Phones
Similar to normal phones but have an RJ-45
(Ethernet) connection instead of the standard
RJ-11 connection
Contains all hardware and software
Connect directly to router
Offices configured with all IP phones are said to
have an IP Private Branch Exchange (PBX) set
up

8. PC To PC
Obtain free or very low-cost software from
companies.
Sender & receiver need equipment.
Need the software, Internet connection
(preferably high speed), microphone, speakers,
and a sound card..
Lower cost once equipment is purchased
PSTN
ISP
Modem USER B
Server
PSTN
ISP
ModemUSER A
Internet

9. IP NetworkMultimedia
PC
Multimedia
PC
Initially, PC to
PC voice calls
over the
Internet
PSTN
Gatew
ay
PSTN
Gate
way
Public Switched
Telephone
Network
Gateways allow
PCs to also
reach phones
…or phones to
reach phones
Working:

10. Advantages
 Ability to concentrate on core business functions
 Automation of routine administrative functions
 Riddance of intra-site long distance expenses
 Reduced administration as well as network costs
 Effective optimization of existing resources
 Elimination of risks associated with vendor lock-
in
 Integrated applications

11. DisAdvantages
Firewalls
UDP
Security
Reliability

12. Conclusion
Cheaper alternative to the conventional
phone services
Easy to implement and maintain
VoIP will likely grow in terms of popularity
but may not replace the standard phone
services
Companies will come out with new
communication services with extensive
features at competitive prices

13. Future Scope
 New communications services.
 Teleconferencing, videoconferencing
and Plantronics headset and iPECS
CM Brochure.