PSTN vs. VoIP

This page intends to give you the opportunity to get to know the PSTN network and VoIP protocol that provide two ways of communication. In the following section you will read about their definitions, how they work and about their features as well.

PSTN (Public Switched Telephone Network) is a communication system that enables users to have telephone service. Users can initiate calls to anyone who also have a subscription to the PSTN system.

VoIP (Voice over Internt Protocol) is a technology that allows you to make telephone calls with the help of an Internet connection instead of analog telephone lines. You can use VoIP service on your mobile phone, on computers and even on ordinary phones with a special adapter.

pstn vs voip
Figure 1 - PSTN vs. VoIP

How VoIP and PSTN Work

Voice over Internet Protocol works with real-time sessions therefore the data is delivered immediately. VoIP calls can be made with VoIP phones that require some kind of adapter that enables the connection. For making and receiving a phone call you are required to have a phone number. VoIP traffic is described by the H.323 protocol that regulates multimedia data transmission over the Internet.

The Public Switched Telephone Network is composed of different computers and they form a network. PSTN transforms voice signals into digital data.

Features of VoIP and PSTN

VoIP provides many useful and interesting features, including caller ID, voicemail, call waiting, call forwarding, last number re-dial, emergency call service, changing phone number, area code selection, contact lists, return call, caller ID blocking, do not disturb, speed dialing, SMS, etc. Unlike in PSTN networks, the features mentioned above are free services. The upgrade of the services only requires Internet connection and bandwidth.

The PSTN network provides similar features and functionalities as VoIP: call waiting, call forwarding, conference calling, display of directory number, call blocking, caller ID blocking, automatic callback, etc. These services usually available for an additional cost and the set of features can be only expanded by providing new equipment. Calls made with PSTN are usually billed per minute.

Equipment Needed

To be able to use VoIP service you need several devices such as broadband Internet connection, a computer, an adapter and a VoIP phone.

For PSTN service you need to have some equipment like inside and extended wiring, telephone, headset, router, PBX switches and also punchdown blocks.

Comparison

PSTN connection is a reliable one because the connection is made through dedicated lines however, VoIP is not as reliable because the service depends on the Internet connection and bandwidth. If you want to add additional features to your PSTN you can do so for an extra charge while VoIP features can be expanded without any charge or for a low cost. Through PSTN only voice can be transmitted and during a VoIP call both voice and video data can be transmitted.

Ozeki Phone System offers a support for both PSTN network and VoIP service. You can have a PSTN service if you attach an ATA adapter to the PBX. You can make VoIP calls if you subscribe at a VoIP provider. Download Ozeki Phone System and you are able to use and exploit its advantages.

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