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Related Keywords
- Analog telephone adapter
- Audio codec
- Authenticate
- Broadband
- Cablemodem
- Comcast Digital Voice
- Communication protocol
- Computer
- Digital audio
- Direct Inbound Dialing
- Encrypt
- Ethernet
- High fidelity
- IP Multimedia Subsystem
- Internet
- Internet Protocol
- Internet protocol
- Multimedia
- Narrowband
- Open Standard
- Open source
- PSTN
- Proprietary protocol
- Public switched telephone network
- Secure telephone
- Session Description Protocol
- Session Initiation Protocol
- Skype protocol
- Smartphones
- Softphone
- Speech coding
- Stereophonic sound
- Streaming media
- Telephone company
- VoIP phone
- Voice communication
Internet Phone
Images : Internet Phone
General Description
Voice over Internet Protocol VoIP, Voice over IP is a general term for a family of methodologies, communication protocols, and transmission technologies for delivery of voice communications and multimedia sessions over Internet Protocol IP networks, such as the Internet. Other terms frequently encountered and synonymous with VoIP are IP telephony, Internet telephony, voice over broadband VoBB , broadband telephony, and broadband phone.
Internet telephony refers to communications services 160 voice, facsimile, and or voice-messaging applications 160 that are transported via the Internet, rather than the public switched telephone network PSTN . The basic steps involved in originating an Internet telephone call are conversion of the analog voice signal to digital format and compression translation of the signal into Internet protocol IP packets for transmission over the Internet the process is reversed at the receiving end.
VoIP systems employ session control protocols to control the set-up and tear-down of calls as well as audio codecs which encode speech allowing transmission over an IP network as digital audio via an audio stream. Codec use is varied between different implementations of VoIP and often a range of codecs are used some implementations rely on narrowband and compressed speech, while others support high fidelity stereo codecs.
Voice over IP has been implemented in various ways using both proprietary and open protocols and standards. Examples of technologies used to implement Voice over IP include
The H.323 protocol was one of the first VoIP protocols that found wide-spread implementation for long-distance traffic, as well as local area network services. However, since the development of newer, less complex protocols, such as MGCP and SIP, H.323 deployments are increasingly limited to carrying existing long-haul network traffic. In particular, the Session Initiation Protocol SIP has gained widespread VoIP market penetration.
A notable proprietary implementation is the Skype protocol, which is in-part based on the principles of peer-to-peer networking.

