Some people may have heard the word Codec used when talking about digital music, digital sound or audio on the Internet. The use of codecs allows millions of people to make and receive phone calls around the world everyday. A Codec short for Code and Decode was a popular term used when digital music came out, remember MP3?
Codec’s do a lot more than just provide a way to code and decode sound for digital music, Codec’s allow millions of phone users around the world to make and receive calls over the Internet. We call these Voice Codec’s.
What is a Voice Codec?
A Voice codec is piece of software that contains a method (an algorithm) for converting voice (speech) into a digital signal for transmission over a data network such as the Internet. That digital transmission is decoded at the receivers end and essentially converted back into sound to allow the recipient to hear that person’s voice.
At ECN, our flagship product ECN Hosted Voice uses Codecs to allow our customers, using business handsets on their office desks to make and receive calls. This is just one great example of how voice Codec’s drive Voice over the Internet.
How does this all work?
Essentially when you speak into an Internet connect phone, the Codec continually samples your voice converting each of these short samples into data packets and sending them over the data network to the receiver.
This sampling occurs up to 50 times each second in a way that the human ear is unable to discern – what you hear is the person talking from the far end but there is a massive amount of technology involved behind the scenes.
Not all Codec’s are the same!
There are different Codec’s for different purposes, some provide excellent almost CD Music quality sound, some compress and squeeze the sound into a small size to improve the transmission of the sound across the world or over poor-quality Internet links.
At ECN we use 2 of the most commonly codecs for MyCloudPBX , these codecs are:
In tech terms, G711 uses 64kbit/s for sending and receiving, using more bandwidth but providing clarity and high-quality sound.
G.729 is a low bandwidth codec using only 8 Kbit/s, the trade-off is a slightly lower perceived speech quality but in the same bandwidth supports nearly 8 more concurrent phone calls.
If you played the G.711 and G.729, you’ll hear a slight difference between the two.