The word "codec" comes from COder/DECoder. A codec defines the algorithm used to convert analog signal into digital signal and vice versa. Each algorithm consumes different amount of bandwidth and provides different voice quality level. In the VoIP world the codecs are used to encode the voice for transmission across an IP backbone. Another name for voip codecs is "vocoders".

A codec is a downloadable software encoder or decoder for a particular media format that is geared towards a specific computer platform. Codecs function much like plugins for browsers, and are used by players or authoring software to work with the specific media type. Most codecs that you will come across are decoders that are geared to presenting media content to players. See similar questions...

In order to transfer voice (analog signal) over IP (internet), the voice message must first be digitized. Codec basically transfers voice into data in order to travel through the public internet network. Presently codec algorithms are designed to reduce the size of their voice packets to increase speeds of transmissions and reduce bandwidth loads on the network. See similar questions...

Depending upon your service, you might be limited only to other subscribers to the service, or you may be able to call anyone who has a telephone number - including local, long distance, mobile, and international numbers. If you are calling someone who has a regular analog phone, that person does not need any special equipment to talk to you. Some VoIP services may allow you to speak with more than one person at a time. See similar questions...

Some VoIP services offer features and services that are not available with a traditional phone, or are available but only for an additional fee. You may also be able to avoid paying for both a broadband connection and a traditional telephone line. See similar questions...

If you're considering replacing your traditional telephone service with VoIP, there are some possible differences: Some VoIP services don't work during power outages and the service provider may not offer backup power. Not all VoIP services connect directly to emergency services through 9-1-1. For additional information, see www.voip911.gov. See similar questions...