Saturday, April 22, 2006
voice over internet protocol
Let us look at technical aspects of the VoIP. When we speak, the sound signal is in the form of analog signal. PSTN networks are used to transmit these analog signals through different modulation techniques. But in VoIP it is converted to a digital signal or you can say to a binary signal. This digital electrical signal is converted into small IP packets at network layer and is transmitted to its destination address through internet modem and gateways. For VoIP we need a broadband internet connection. In this voice and data signals are transmitted simultaneously. This is a packet switched network. In this data or voice signal is transmitted through IP packets. Each IP packet take its own route depending upon routing algorithms and congestion on different routes.
These IP Packets reorders at the destination point using header valves in the address fields. These are packet are reconverted to a digital electrical signal and then to an analog voice signal through your telephone.
The main benefit of VoIP is its low cost of operation. Only expenditure is on internet connection. Your telephone bill can be reduced by 95% through a VoIP connection. The software required for this is also almost free and is available as open source. The one major aspect of it is that you are bypassing the phone company (and its charges) entirely. VoIP providers like Vonage have already been around for a little while and are growing rapidly. But as every coin has two sides it has its own demerits too. The voice quality is on the lower side.
There are three ways to place a VoIP call:
- First is using a special VoIP adapter called analog telephone adapter also ATA. Through ATA you can connect your computer to your telephone at one end and to your computer internet connection on the other end. It converts an analog signal to a digital signal. It takes the analog sound signal from your traditional telephone and converts it into digital electrical signal for transmission over the Internet. Some of VoIP service providers makes these ATAs available for free. Its installation is also very simple. Get the adapter out of its box, Plug the phone cable into it, And hurray you are ready to talk for infinite time without worrying about your phone bill.
- The other way is through IP Phones. These are almost similar like traditional phones with one major difference. Traditional Phones have an RJ 11(registered jack) connector. But IP phones have an RJ 45 Connector with them. IP phones are required to be connected directly to the modem or router.
- The last way is also easiest to use and install. Only accessories that you require for them is microphone, speaker, Software ( you can get it for free or at minimal price) amd an internet connection. You wont require to pay for your call even. Apart from your normal monthly ISP bill, there is usually no charge at all for computer-to-computer VoIP call irrespective of the distance.
VoIP Spear shows your QoS in easy-to-read charts. You can also have it send you email alerts when your quality drops too low.
VoIP Spear (www.voipspear.com) is free for personal use.