Q

Relationship between codec and VoIP

What is the relationship between codec and VoIP?
Codec is short for 'encoder and decoder'. When a person speaks, a continuous signal is generated. This signal can be directly sent over an analog line. To send speech over a digital interface, the continuous signal has to be converted into a digital form. To do this, some samples of the analog signal are taken (enough to adequately reconstruct the original analog signal at the far end). These samples are then encoded for transmission. There are multiple ways to encode a speech signal. For example, the ITU standard G.711 is one way to encode so that the speech samples are not compressed. To save bandwidth, the ITU standard G.729 can be used which applies a compression algorithm to the speech samples. Once encoded, the speech is put into packets which are transmitted across an IP network. This is the action of transmitting voice over IP. At the receiver, the packet is received and the information is decoded using the appropriate codec (G.711 or G.729 are examples of codecs).
This was first published in March 2005

Dig deeper on Unified Communications Resources

Pro+

Features

Enjoy the benefits of Pro+ membership, learn more and join.

Have a question for an expert?

Please add a title for your question

Get answers from a TechTarget expert on whatever's puzzling you.

You will be able to add details on the next page.

0 comments

Oldest 

Forgot Password?

No problem! Submit your e-mail address below. We'll send you an email containing your password.

Your password has been sent to:

SearchMobileComputing

SearchNetworking

SearchTelecom

SearchITChannel

SearchEnterpriseWAN

SearchExchange

Close