The Principles of VoIP

The Voice Over IP continues to collect more streamyx accounts more consensus in the companies. It allows indeed reducing operating costs and investment in infrastructure and also an increase in productivity by adding new features.

But how does VoIP from a technical point streamyx configuration view? The item, in streamyx mail setting to be transmitted via Skype or bangsar kl protocols phone, requires the digitization of sound that dctt streamyx com collected by a microphone and reproduced, at the other end, from a loudspeaker built into a headset, in a sound box or a telephone.

For the digitization and subsequent reconstruction of voice you use the sound card integrated into computer or external sound cards in the form of appendices or USB phones with USB interface direct or indirect (through a cordless as in the case of this lesson).

The importance codecs - The encoding and decoding is performed by special programs, such codec. There are different and the type used for voice is the G.729 that compresses any sound in blocks lasting 10 milliseconds each. It is used especially for VoIP conversations and encoding sound with a speed of 8 Kbit per second.

This is a frequency coding not suitable for play music or even just to send faxes, but sufficient to transfer voice conversations. We recall here that the human voice occupies only a fraction of the "spectrum" (together) of frequencies that the ear can hear. For the record, the human voice ranges from 300 to 3,400 hertz (cycles per second) while all sounds audible ranges from 20 to 20,000 Hz.

Therefore, it is considered that the digitization of voice is enough to have a channel from 4 kHz at which combine two bands side kept free to prevent interference. With debts Auditors thus arrives at a sampling rate of 8 KHz, which is the system that converts the original sound into digital pulses withdraws 8,000 samples per second that are then processed by the G.729 codec, which produces packages from 10 milliseconds composed of 20 bytes each.

The protocols used - The packages are then grouped in pairs and routed on the Internet using a typical three protocols: IP, UDP (User Datagram Protocol) or RTP (Real-time Transport Protocol) that add another 40 bytes per packet. When you must leave on the ADSL line must encapsulate packages in PPP (Point to Point Protocol).

This is an encapsulation additional necessary to manage a communication between two fixed points (the connection between the router and service provider). tmnet password addition brings other 7 +4 bytes per packet. By adding all subsequent packets see that a channel for conveying voice quality standard we want to 34.4 Kbit per second.

Visit my site for further information about Pocket PC & Smartphone Technology

David Beckham insists he will never call time on England after five star hotels kuala lumpur resurrecting his international career under Fabio Capello...