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T.38
T.38 is an ITU recommendation for allowing transmission of fax over IP networks (FoIP) in real time. History The T.38 fax relay standard was devised in 1998 as a way to permit faxes to be transported across IP networks between existing Group 3 (G3) fax terminals. T.4 and related fax standards were published by the ITU in 1980, before the rise of the Internet. In the late 1990s, VoIP, or Voice over IP, began to gain ground as an alternative to the conventional Public Switched Telephone Network (PSTN). However, because most VoIP systems are optimized (through their use of aggressive lossy bandwidth-saving compression) for voice rather than data calls, conventional fax machines worked poorly or not at all on them due to the network impairments such as delay, jitter, packet loss, and so on. Thus, some way of transmitting fax over IP was needed. Overview In practical scenarios, a T.38 fax call has at least part of the call being carried over PSTN, although this is not required ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
FoIP
T.38 is an ITU recommendation for allowing transmission of fax over IP networks (FoIP) in real time. History The T.38 fax relay standard was devised in 1998 as a way to permit faxes to be transported across IP networks between existing Group 3 (G3) fax terminals. T.4 and related fax standards were published by the ITU in 1980, before the rise of the Internet. In the late 1990s, VoIP, or Voice over IP, began to gain ground as an alternative to the conventional Public Switched Telephone Network (PSTN). However, because most VoIP systems are optimized (through their use of aggressive lossy bandwidth-saving compression) for voice rather than data calls, conventional fax machines worked poorly or not at all on them due to the network impairments such as delay, jitter, packet loss, and so on. Thus, some way of transmitting fax over IP was needed. Overview In practical scenarios, a T.38 fax call has at least part of the call being carried over PSTN, although this is not require ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Internet Fax
Internet fax, e-fax, or online fax is the use of the internet and internet protocols to send a fax (facsimile), rather than using a standard telephone connection and a fax machine. A distinguishing feature of Internet fax, compared to other Internet communications such as email, is the ability to exchange fax messages with traditional telephone-based fax machines. Purpose Fax has no technical advantage over other means of sending information over the Internet, using technologies such as email, scanner, and graphics file formats; however, it is extremely simple to use: put the documents to be faxed in a hopper, dial a phone number, and press a button. Fax continues to be used over the telephone network at locations without computer and Internet facilities; and sometimes a fax of a document with a person's handwritten signature is a requirement for legal reasons. Faxes can be sent from electronic devices, often referred to as online faxing which allows faxes to be sent and received ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
VoIP
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 protocol ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
VoIP Protocols
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 t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
ITU-T Recommendations
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 of the Uni ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fax Server
A fax server is a system installed in a local area network (LAN) server that allows computer users whose computers are attached to the LAN to send and receive fax messages. Alternatively the term ''fax server'' is sometimes used to describe a program that enables a computer to send and receive fax messages, set of software running on a server computer which is equipped with one or more fax-capable modems (or dedicated fax boards) attached to telephone lines or, more recently, software modem emulators which use T.38 ("Fax over IP") technology to transmit the signal over an IP network. Its function is to accept documents from users, convert them into faxes, and transmit them, as well as to receive fax calls and either store the incoming documents or pass them on to users. Users may communicate with the server in several ways, through either a local network or the Internet. In a big organization with heavy fax traffic, the computer hosting the fax server may be dedicated to that fun ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Session Initiation Protocol
The Session Initiation Protocol (SIP) is a signaling protocol used for initiating, maintaining, and terminating communication sessions that include voice, video and messaging applications. SIP is used in Internet telephony, in private IP telephone systems, as well as mobile phone calling over LTE (VoLTE). The protocol defines the specific format of messages exchanged and the sequence of communications for cooperation of the participants. SIP is a text-based protocol, incorporating many elements of the Hypertext Transfer Protocol (HTTP) and the Simple Mail Transfer Protocol (SMTP). A call established with SIP may consist of multiple media streams, but no separate streams are required for applications, such as text messaging, that exchange data as payload in the SIP message. SIP works in conjunction with several other protocols that specify and carry the session media. Most commonly, media type and parameter negotiation and media setup are performed with the Session Descripti ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Session Description Protocol
The Session Description Protocol (SDP) is a format for describing multimedia communication sessions for the purposes of announcement and invitation. Its predominant use is in support of streaming media applications, such as voice over IP (VoIP) and video conferencing. SDP does not deliver any media streams itself but is used between endpoints for negotiation of network metrics, media types, and other associated properties. The set of properties and parameters is called a ''session profile''. SDP is extensible for the support of new media types and formats. SDP was originally a component of the Session Announcement Protocol (SAP), but found other uses in conjunction with the Real-time Transport Protocol (RTP), the Real-time Streaming Protocol (RTSP), Session Initiation Protocol (SIP), and as a standalone protocol for describing multicast sessions. The IETF published the original specification as a Proposed Standard in April 1998. Revised specifications were released in 2006 (R ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Asterisk (PBX)
Asterisk is a software implementation of a private branch exchange (PBX). In conjunction with suitable telephony hardware interfaces and network applications, Asterisk is used to establish and control telephone calls between telecommunication endpoints, such as customary telephone sets, destinations on the public switched telephone network (PSTN), and devices or services on voice over Internet Protocol (VoIP) networks. Its name comes from the asterisk (*) symbol for a signal used in dual-tone multi-frequency (DTMF) dialing. Asterisk was created in 1999 by Mark Spencer of Digium, which since 2018 is a division of Sangoma Technologies Corporation. Originally designed for Linux, Asterisk runs on a variety of operating systems, including NetBSD, OpenBSD, FreeBSD, macOS, and Solaris, and can be installed in embedded systems based on OpenWrt. Features The Asterisk software includes many features available in commercial and proprietary PBX systems: voice mail, conference callin ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Freeswitch
FreeSWITCH is free and open-source server software for real-time communication applications, including WebRTC, video, and voice over Internet Protocol (VoIP). It runs on Linux, Windows, macOS, and FreeBSD. FreeSWITCH is used to build private branch exchange (PBX) telecommunication systems, IVR services, videoconferencing with chat and screen sharing, wholesale least-cost routing, Session Border Controller (SBC) and embedded communication appliances. It has support for encryption, ZRTP, DTLS, and Session Initiation Protocol (SIP). It is implemented as a core library, libfreeswitch, which can be embedded into other projects. It is distributed under the Mozilla Public License (MPL), a free software license. History The FreeSWITCH project was announced in January 2006 at O'Reilly Media's ETEL Conference. In June 2007, FreeSWITCH was selected by Truphone for use, and in August 2007, Gaboogie announced that it selected FreeSWITCH as its conferencing platform. The official rel ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Telecommunications
Telecommunication is the transmission of information by various types of technologies over wire, radio, optical, or other electromagnetic systems. It has its origin in the desire of humans for communication over a distance greater than that feasible with the human voice, but with a similar scale of expediency; thus, slow systems (such as postal mail) are excluded from the field. The transmission media in telecommunication have evolved through numerous stages of technology, from beacons and other visual signals (such as smoke signals, semaphore telegraphs, signal flags, and optical heliographs), to electrical cable and electromagnetic radiation, including light. Such transmission paths are often divided into communication channels, which afford the advantages of multiplexing multiple concurrent communication sessions. ''Telecommunication'' is often used in its plural form. Other examples of pre-modern long-distance communication included audio messages, such as coded d ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
