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Tandem Free Operation
Tandem Free Operation (TFO) is a part of ETSI's 3GPP standard specification, which has been included from R99 of the standards specifications onwards. Overview In traditional GSM networks, a call between two Mobile Stations (MS) involve a dual encoding/decoding process. Speech signals are first encoded in the originating MS, converted to G.711 in the local transcoder, converted back to a GSM codec in the remote transcoder and finally converted back to speech at the terminating MS. In this configuration the two transcoders are operating in tandem introducing a voice quality degradation. It is possible to eliminate this problem by removing the two transcoding operations in the voice path if the two MS are using the same codec. Details Broadly, the equipments that are en-route two end mobile sets can be categorized into two types: * Active voice equipments, that does the transcoding operation, either from a GSM/UMTS speech codec (e.g.: GSM-EFR, GSM-AMR) to G.711/PCM or opposite. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
GSM-AMR
The Adaptive Multi-Rate (AMR, AMR-NB or GSM-AMR) audio codec is an audio compression format optimized for speech coding. AMR speech codec consists of a multi-rate narrowband speech codec that encodes narrowband (200–3400 Hz) signals at variable bit rates ranging from 4.75 to 12.2 kbit/s with toll quality speech starting at 7.4 kbit/s. AMR was adopted as the standard speech codec by 3GPP in October 1999 and is now widely used in GSM and UMTS. It uses link adaptation to select from one of eight different bit rates based on link conditions. AMR is also a file format for storing spoken audio using the AMR codec. Many modern mobile telephone handsets can store short audio recordings in the AMR format, and both Free software, free and proprietary programs exist (see #Software support, Software support) to convert between this and other formats, although AMR is a speech format and is unlikely to give ideal results for other audio. The common filename extension is .amr. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Line Echo Canceller
Line most often refers to: * Line (geometry), object with zero thickness and curvature that stretches to infinity * Telephone line, a single-user circuit on a telephone communication system Line, lines, The Line, or LINE may also refer to: Arts, entertainment, and media Films * ''Lines'' (film), a 2016 Greek film * ''The Line'' (2017 film) * ''The Line'' (2009 film) * ''The Line'', a 2009 independent film by Nancy Schwartzman Podcasts * ''The Line'' (podcast), 2021 by Dan Taberski Literature * Line (comics), a term to describe a subset of comic book series by a publisher * ''Line'' (play), by Israel Horovitz, 1967 * Line (poetry), the fundamental unit of poetic composition * "Lines" (poem), an 1837 poem by Emily Brontë * ''The Line'' (memoir), by Arch and Martin Flanagan * ''The Line'' (play), by Timberlake Wertenbaker, 2009 Music Albums * ''Lines'' (The Walker Brothers album), 1976 * ''Lines'' (Pandelis Karayorgis album), 1995 * ''Lines'' (Unthanks album), 201 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Internet Protocol
The Internet Protocol (IP) is the network layer communications protocol in the Internet protocol suite for relaying datagrams across network boundaries. Its routing function enables internetworking, and essentially establishes the Internet. IP has the task of delivering packets from the source host to the destination host solely based on the IP addresses in the packet headers. For this purpose, IP defines packet structures that encapsulate the data to be delivered. It also defines addressing methods that are used to label the datagram with source and destination information. IP was the connectionless datagram service in the original Transmission Control Program introduced by Vint Cerf and Bob Kahn in 1974, which was complemented by a connection-oriented service that became the basis for the Transmission Control Protocol (TCP). The Internet protocol suite is therefore often referred to as ''TCP/IP''. The first major version of IP, Internet Protocol Version 4 (IPv4), is the do ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
PSTN
The public switched telephone network (PSTN) provides infrastructure and services for public telecommunication. The PSTN is the aggregate of the world's circuit-switched telephone networks that are operated by national, regional, or local telephony operators. These consist of telephone lines, fiber optic cables, microwave transmission links, cellular networks, communications satellites, and undersea telephone cables, all interconnected by switching centers which allow most telephones to communicate with each other. Originally a network of fixed-line analog telephone systems, the PSTN is now almost entirely digital in its core network and includes mobile and other networks, as well as fixed telephones. The technical operation of the PSTN adheres to the standards created by the ITU-T. These standards allow different networks in different countries to interconnect seamlessly. The E.163 and E.164 standards provide a single global address space for telephone numbers. The combinat ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
