Difference between VoIP and PSTN

1. Voice Over Internet Protocol (VoIP) :
VoIP stands for Voice Over Internet Protocol also called as IP telephony or Internet telephony or Broadband telephony. In simple it refers to the Phone service over Internet. This technology allows to make voice call using broadband internet connection instead of regular phone line. It is used for delivery of high range voice communications as well as multimedia sessions over Internet Protocol (IP) networks that’s why it is called as Voice over IP. Now it is one of the most effective way of delivering voice between people.

In VoIP Internet is used as the transmission medium for telephone calls by sending voice data in the form of packets using (Internet Protocol) IP. It transmits real time voice signal from source IP address to the target IP address. In the current days Voice Over Internet Protocol (VoIP) is one of the reliable, and cost-effective alternative to early/traditional phone service.

2. Public Switched Telephone Network (PSTN) :
PSTN stands for Public Switched Telephone Network also known as traditional circuit-switched telephone network formerly it was known as only Public Telephone Network. PSTN refers to a telecommunications network which allows voice communication between people at different sites. Public Switched Telephone Network uses an old technology which uses copper wires to carry analog voice signal. It is operated by local, national and international carriers.

Public Switched Telephone Network is based on Circuit Switching concept. When a dedicated path is established between two phones a circuit is established between them. All Landlines are Public Switched Telephone Network (PSTN).



Difference between VoIP and PSTN :



S.No. VoIP PSTN
01. Voice over Internet Protocol uses packet switching. Public Switched Telephone Network uses circuit switching.
02. In VoIP, only an internet connection is required. In PSTN, dedicated lines required from telecom company.
03. No dedicated path required between sender and receiver. Dedicated path required between sender and receiver.
04. One VoIP lines require 100 kbps. One link typically supports 64 kbps.
05. In VoIP, it acquires and releases bandwidth as it is needed. Bandwidth is reserved in advance it requires as each line is 64 kbps.
06. In VoIP, Cost is not dependent on distance and time. In PSTN, Cost is based on distance and time.
07. Extensions is a standard feature of VoIP. Extensions requires extra costs in PSTN.
08. VoIP provides consistent voice quality but depends on bandwidth. PSTN provides consistent voice quality.
09. Call waiting, call forwarding, call transfer are standard features of VoIP. Call waiting, call forwarding, call transfer are usually standard features in PSTN but sometimes it costs extra for this.
10. Scalability and upgrades requires improved internet bandwidth. Scalability and upgrades requires substantial hardware additions.

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I am a Computer Science Engineering student, have a great interest in android application development & now mostly focusing on Internet of Things (IoT) applications

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