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H.323
H.323 is a recommendation from the ITU Telecommunication Standardization Sector (ITU-T) that defines the protocols to provide audio-visual communication sessions on any packet network. The H.323 standard addresses call signaling and control, multimedia transport and control, and bandwidth control for point-to-point and multi-point conferences. It is widely implemented by voice and videoconferencing equipment manufacturers, is used within various Internet real-time applications such as GnuGK and NetMeeting and is widely deployed worldwide by service providers and enterprises for both voice and video services over IP networks. It is a part of the ITU-T H.32x series of protocols, which also address multimedia communications over ISDN, the PSTN or SS7, and 3G mobile networks. H.323 call signaling is based on the ITU-T Recommendation Q.931 protocol and is suited for transmitting calls across networks using a mixture of IP, PSTN, ISDN, and QSIG over ISDN. A call model, similar ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Registration, Admission And Status
H.323 is a recommendation from the ITU Telecommunication Standardization Sector (ITU-T) that defines the protocols to provide audio-visual communication sessions on any packet network. The H.323 standard addresses call signaling and control, multimedia transport and control, and bandwidth control for point-to-point and multi-point conferences. It is widely implemented by voice and videoconferencing equipment manufacturers, is used within various Internet real-time applications such as GnuGK and NetMeeting and is widely deployed worldwide by service providers and enterprises for both voice and video services over IP networks. It is a part of the ITU-T H.32x series of protocols, which also address multimedia communications over ISDN, the PSTN or SS7, and 3G mobile networks. H.323 call signaling is based on the ITU-T Recommendation Q.931 protocol and is suited for transmitting calls across networks using a mixture of IP, PSTN, ISDN, and QSIG over ISDN. A call model, similar ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
GnuGK
GNU Gatekeeper (abbreviated as GnuGk) is a free software project that implements an H.323 Gatekeeper based on the OpenH323 or H323Plus stack. A gatekeeper provides address translation, admissions control, call routing, authorization and accounting services to an H.323 system defined on the H.323 standard by ITU-T. Features GnuGk's set of features include: * Created for Linux, Windows, macOS, Solaris, FreeBSD, OpenBSD and NetBSD * A policy-based flexible routing mechanism * Calling and called numbers rewriting, including CLI rewriting * Full H.323 proxy, including Real-time Transport Protocol (RTP) and RTP Control Protocol (RTCP) media channels, and T.120 data channels * NAT traversal using a number of protocols, including H.460.17, H.460.18 and H.460.19 * IPv6 support (incl. IPv4-IPv6 proxying) * LDAP directory support (H.350) * Call retry-failover * Clustering support by neighbors, parent-child, alternates GK * Transmission Control Protocol (TCP) status port for monitoring and ex ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
IP Telephony
Voice over Internet Protocol (VoIP), also called IP telephony, is a method and group of technologies for the delivery of voice communications and multimedia sessions over Internet Protocol (IP) networks, such as the Internet. The terms Internet telephony, broadband telephony, and broadband phone service specifically refer to the provisioning of communications services (voice, fax, SMS, voice-messaging) over the Internet, rather than via the public switched telephone network (PSTN), also known as plain old telephone service (POTS). Overview The steps and principles involved in originating VoIP telephone calls are similar to traditional digital telephony and involve signaling, channel setup, digitization of the analog voice signals, and encoding. Instead of being transmitted over a circuit-switched network, the digital information is packetized and transmission occurs as IP packets over a packet-switched network. They transport media streams using special media delivery protocols th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Voice Over IP
Voice over Internet Protocol (VoIP), also called IP telephony, is a method and group of technologies for the delivery of speech, voice communications and multimedia sessions over Internet Protocol (IP) networks, such as the Internet. The terms Internet telephony, broadband telephony, and broadband phone service specifically refer to the provisioning of communications services (voice, fax, Short Message Service, SMS, voice-messaging) over the Internet, rather than via the public switched telephone network (PSTN), also known as plain old telephone service (POTS). Overview The steps and principles involved in originating VoIP telephone calls are similar to traditional digital telephony and involve signaling, channel setup, digitization of the analog voice signals, and encoding. Instead of being transmitted over a circuit-switched network, the digital information is packetized and transmission occurs as IP packets over a packet-switched network. They transport media streams using spec ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Videoconferencing
Videotelephony, also known as videoconferencing and video teleconferencing, is the two-way or multipoint reception and transmission of audio signal, audio and video signals by people in different locations for Real-time, real time communication.McGraw-Hill Concise Encyclopedia of EngineeringVideotelephony McGraw-Hill, 2002. Retrieved from the FreeDictionary.com website, January 9, 2010 A videophone is a telephone with a video camera and Display device, video display, capable of simultaneous video and audio communication. Videoconferencing implies the use of this technology for a group or organizational meeting rather than for individuals, in a videoconference.Mulbach et al, 1995. pg. 291. Telepresence may refer either to a high-quality videotelephony system (where the goal is to create the illusion that remote participants are in the same room) or to meetup technology, which can go beyond video into robotics (such as moving around the room or physically manipulating objects). Vide ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Videophone
Videotelephony, also known as videoconferencing and video teleconferencing, is the two-way or multipoint reception and transmission of audio and video signals by people in different locations for real time communication.McGraw-Hill Concise Encyclopedia of EngineeringVideotelephony McGraw-Hill, 2002. Retrieved from the FreeDictionary.com website, January 9, 2010 A videophone is a telephone with a video camera and video display, capable of simultaneous video and audio communication. Videoconferencing implies the use of this technology for a group or organizational meeting rather than for individuals, in a videoconference.Mulbach et al, 1995. pg. 291. Telepresence may refer either to a high-quality videotelephony system (where the goal is to create the illusion that remote participants are in the same room) or to meetup technology, which can go beyond video into robotics (such as moving around the room or physically manipulating objects). Videoconferencing has also been called "visu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Private Branch Exchange
A business telephone system is a multiline telephone system typically used in business environments, encompassing systems ranging in technology from the key telephone system (KTS) to the private branch exchange (PBX). A business telephone system differs from an installation of several telephones with multiple central office (CO) lines in that the CO lines used are directly controllable in key telephone systems from multiple telephone stations, and that such a system often provides additional features related to call handling. Business telephone systems are often broadly classified into key telephone systems, and private branch exchanges, but many hybrid systems exist. A key telephone system was originally distinguished from a private branch exchange in that it did not require an operator or attendant at the switchboard to establish connections between the central office trunks and stations, or between stations. Technologically, private branch exchanges share lineage with centra ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
NetMeeting
Microsoft NetMeeting is a discontinued VoIP and multi-point videoconferencing client included in many versions of Microsoft Windows (from Windows 95 OSR2 to Windows Vista). It uses the H.323 protocol for videoconferencing, and is interoperable with OpenH323-based clients such as Ekiga, OpenH323, and Internet Locator Service (ILS) as reflector. It also uses a slightly modified version of the T.120 Protocol for whiteboarding, application sharing (or by extension, desktop sharing), and file transfers. History NetMeeting was released on May 29, 1996, originally bundled with Internet Explorer 3, and later with Internet Explorer 4. It incorporates technology acquired by Microsoft from UK software developer Data Connection Ltd and DataBeam Corporation (subsequently acquired by Lotus). Before video service became common on free IM clients, such as Yahoo! Messenger and MSN Messenger, NetMeeting was a popular way to perform video conferences and chatting over the Internet (with the hel ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Real-time Transport Protocol
The Real-time Transport Protocol (RTP) is a network protocol for delivering audio and video over IP networks. RTP is used in communication and entertainment systems that involve streaming media, such as telephony, video teleconference applications including WebRTC, television services and web-based push-to-talk features. RTP typically runs over User Datagram Protocol (UDP). RTP is used in conjunction with the RTP Control Protocol (RTCP). While RTP carries the media streams (e.g., audio and video), RTCP is used to monitor transmission statistics and quality of service (QoS) and aids synchronization of multiple streams. RTP is one of the technical foundations of Voice over IP and in this context is often used in conjunction with a signaling protocol such as the Session Initiation Protocol (SIP) which establishes connections across the network. RTP was developed by the Audio-Video Transport Working Group of the Internet Engineering Task Force (IETF) and first published in 1996 a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
ITU-T
The ITU Telecommunication Standardization Sector (ITU-T) is one of the three sectors (divisions or units) of the International Telecommunication Union (ITU). It is responsible for coordinating standards for telecommunications and Information Communication Technology such as X.509 for cybersecurity, Y.3172 and Y.3173 for machine learning, and H.264/MPEG-4 AVC for video compression, between its Member States, Private Sector Members, and Academia Members. The first meeting of the World Telecommunication Standardization Assembly (WTSA), the sector's governing conference, took place on 1 March of that year. ITU-T has a permanent secretariat called the Telecommunication Standardization Bureau (TSB), which is based at the ITU headquarters in Geneva, Switzerland. The current director of the TSB is Chaesub Lee (of South Korea), whose first 4-year term commenced on 1 January 2015, and whose second 4-year term commenced on 1 January 2019. Chaesub Lee succeeded Malcolm Johnson (Director), Malc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Call Pickup
Call pick-up is a feature used in a telephone system that allows one to answer someone else's telephone call. The feature is accessed by pressing a pre-programmed button (usually labelled "Pick-Up"), or by pressing a special sequence of buttons on the telephone set. In places where call pick-up is used, the telephone sets may be divided into ''zones''. Under such an arrangement, using call pick-up will only pick up a call in the same zone. Call pick-up can be ''directed''. Directed call pick-up is used for picking up a call that is ringing at a specific extension number; this feature is accessed through a different sequence of buttons than normal call pick-up. A telephone set can only pick up one call at one time. If there are many incoming calls at the same time, call pick-up will pick up the call that rang first unless the pick-up is directed. Uses of call pickup * If a colleague's telephone set is ringing, one can answer that call by picking up one's own set and then using ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sound
In physics, sound is a vibration that propagates as an acoustic wave, through a transmission medium such as a gas, liquid or solid. In human physiology and psychology, sound is the ''reception'' of such waves and their ''perception'' by the brain. Only acoustic waves that have frequencies lying between about 20 Hz and 20 kHz, the audio frequency range, elicit an auditory percept in humans. In air at atmospheric pressure, these represent sound waves with wavelengths of to . Sound waves above 20 kHz are known as ultrasound and are not audible to humans. Sound waves below 20 Hz are known as infrasound. Different animal species have varying hearing ranges. Acoustics Acoustics is the interdisciplinary science that deals with the study of mechanical waves in gasses, liquids, and solids including vibration, sound, ultrasound, and infrasound. A scientist who works in the field of acoustics is an ''acoustician'', while someone working in the field of acoustica ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
