How data handling is done in VOIP ?

How data handling is done in VOIP ?
What is VOIP?
Because of cost and advantages to consumers over integrated telephone networks VOIP has become much popular. Have you ever heard about How Americans pay monthly local telephone fee??  Yeah.. Americans pay monthly local fee calls per minute charge for long distance calls. Most internet connections are charged only using flat monthly or yearly fee structure. Using this facility i.e. Internet connection for both data traffic and voice calls can allow to pay down payment i.e. once in a month. This is what about

VOIP.
Now come to data handling? My question how data handling is done in voip??
In the ordinary phone system a call must be place before any voice is ready to sent .In this process this outgrowth involves dialing the digits of the titled signal, which are then processed by the telephone company's system to ring the called number. With VOIP, the somebody moldiness enter the dialed confine, which can see the forum of a merchandise dialed on a telephone keypad or the pick of a Universal Resource Indicator (URI), but after that a interlacing periodical of packet exchanges must occur, which is completely based on VOIP signaling protocol. The main difficulty is different systems are addressed using their unique IP addresses. But the user one who enters an ordinary telephone number or URI to dialed the call. The telephone which the user is going to dialed or URI should be linked with an IP address to reach the called party. For example nist.gov must be linked to the IP address of the NIST web server. A number of protocols are embroiled in determining the IP address that corresponds to the called party's telephone number.

From the above the figure once the called party responds , voice must be converted in to digital form that voice should be in 0's and 1's. This segmented voice signal will be in streams of packets. What it is happening here is the voice signal which is from called party is converted in to analog voice signals to digital, Using A-D converter. Now the digitized signal will be in digits. It occupies very less space. And these samples can be inserted into data packets to be transferred on the Internet. The protocol for the voice packets is typically the Real-time Transport Protocol, RTP (RFC 3550).
 These above mentioned packets have   header fields that carry data needed to correctly re arrange the packets   to voice signal on the other end. That is in other end the signal is again converted to Voice signal.. That is from digital to voice. But voice packets will be transferred payload by UDP protocols which are used for data transmission. Lastly the digitized voice signal which has been converted from digital to analog is used by third party's handset speaker.
This is how data handling is done in VOIP and also data transferring from one system to another system..

The whole module can be explained in one line as follows:
Input signal which is Voice is converted to Digital signal using A-D converter. This digital signal is again converted to Analog  i.e voice signal.. This is data transmission or data handling is done in VOIP.