The Internet telephony system is a category of hardware and software that enables us to use “Internet” as the transmission medium for making long distance telephone calls. It provides free telephone calls to anywhere in the world to the users who have free or fixed line internet access.
Internet telephony refers to the use of the public internet for voice transmission. That is, it enables the subscriber of an Internet Service to use his or her computer to make long distance calls. The quality of this telephone service is not at par with the direct telephone connections as yet.
We can make telephone calls over the Internet in two ways as follows:
1. In this way, we use our computer and special hardware as well as software to make calls so that one can communicate through the PC.
2. In second way which often referred as Internet Telephony, where one make a phone call as one does normally through a regular telephone except the voice call is routed over the internet rather than through the normal phone service.
Internet telephony usually cuts the cost of making long distance phone calls. The revolutionary part of using is the internet to make phone calls from your PCs is the price. Which is virtually equals to zero or free. Here the user pays only for the internet charges which are very nominal as in case of web browsing or sending an email. User needn’t actually have to pay for the phone call itself.
Here one user can make call to anywhere in the world. Internet telephony makes use of the Internet Protocol(IP) which allows the computers to communicate with each other throughout the world which has got basic internet connection at least.
In today’s market there are various software available which facilitates such features such as Skype, Gtalk, Cool Talk, NetMeeting, etc.. Many other applications are also coming as bundled with the Web Browser and other standalone products. Internet telephony products are sometimes called as IP Telephony, Voice over the Internet(VOI) or Voice over IP(VOIP). It is transported through Internet rather than the public switched telephone network(PSTN). This provides the flexibility of sending Voice Call, FAX, SMS, etc.
There are three types of Internet telephony system basically used. These are, software based VOIP, Physical IP Phones, mobile & integrated VOIP. The main disadvantage of Internet telephony as the service will disrupt if there is power failure.