Coherent Contributes to G.IEC - Paving the Way for New Echo Canceller Recommendations.LEESBURG, Va.--(BUSINESS WIRE)--July 29, 1996--Leading voice enhancement and echo cancellation The elimination of an echo in a two-way voice transmission. Echo is created in the telephone company's central office switch when two-wire lines from the customer are converted to four-wire lines for backbone trunks. specialist, Coherent Communications Systems Corporation of Leesburg, Virginia Leesburg is a historic town and is the county seat of Loudoun County, Virginia, United States of America. Located approximately 40 miles west-northwest of Washington, D.C. , has been actively contributing to the new set of International Telecommunications Union See ITU. (body, standard) International Telecommunications Union - (ITU) ITU-T, the telecommunication standardisation sector of ITU, is responsible for making technical recommendations about telephone and data (including fax) communications systems for PTTs and suppliers. (ITU (International Telecommunication Union, Geneva, Switzerland, www.itu.ch) A telecommunications standards body that is under the auspices of the United Nations. Comprising more than 185 member countries, the ITU sets standards for global telecom networks. ) Recommendations on Echo Cancellers, via Study Group 15. The results of four years' work are encapsulated in document G.IEC (International Electrotechnical Commission, Geneva, Switzerland, www.iec.ch) An organization that sets international electrical and electronics standards founded in 1906. It is made up of national committees from over 60 countries. IEC - International Electrotechnical Commission , which is awaiting ratification by the ITU membership before being formally adopted as an ITU Recommendation. Coherent's resident expert on ITU matters, Jerry Skene skene In ancient Greek theatre, a building behind the playing area that was originally a hut in which actors changed masks and costumes. It eventually became the scenic backdrop for the drama. First used c. , Vice President Business Development, commented on the significance of the new G.IEC document: "The main rationale behind Study Group 15's work has been to improve the range of tests used to reflect actual network conditions in all of their international complexity that we see today. G.IEC goes further than the previous G.165 document, refining each test and its implementation to ensure that the echo canceller will perform under a wider range of network conditions than specified in G.165. "These tests simulate actual performance on voice, FAX and residual acoustic echo signals in wireline and mobile networks. The result is that the new tests will reflect the real-world environment much more accurately - particularly in the context of increased signal levels. We have identified and simulated the most important echo canceller performance issues and characteristics, and have provided a much more comprehensive representation of the echo canceller's real function in the network." Coherent has been an active participant in the ITU for many years, making a significant contribution to the process of improving international standards, as well as ensuring that its products meet and exceed the benchmarks set by the ITU for echo cancellation performance. In summary, the G.IEC focuses on five principal test areas: - rapid convergence of the echo canceller model when encountering a signal - subjective low returned or residual echo level during single talk performance - low divergence of the model during double-talk performance - assured double-talk detection to prevent voice clipping - proper operation during facsimile transmission. The new series of tests will simulate a more complex tail circuit to emulate actual network conditions by using a Composite Source Signal (CSS (1) See Cascading Style Sheets. (2) (Content Scrambling System) The copy protection system applied to DVDs, which uses a 40-bit key to encrypt the movie. ) instead of plain white noise to simulate speech, while raising the maximum test signal level to 0dBO. These contribute towards more effective testing to improve speech quality and network performance in G.IEC compliant echo cancellers. Coherent Communications Systems Corporation is a worldwide leader in state of the art voice enhancement technology, spanning echo cancellation platforms and associated network software. The Company's products are used globally by major commercial telecommunications companies and network operators, including AT&T Wireless, Cellular One, British Telecom The telephone and communications carrier that provides services in Great Britain and Northern Ireland. It used to be a division of the British Post Office, but was privatized in 1984 under Margaret Thatcher's administration. , Nokia, Telia, Mercury, Cable & Wireless, Telmex, StrataCom, Deutsche Telekom and France Telecom among the extensive list. Coherent is a fully accredited accredited recognition by an appropriate authority that the performance of a particular institution has satisfied a prestated set of criteria. accredited herds cattle herds which have achieved a low level of reactors to, e.g. ISO (1) See ISO speed. (2) (International Organization for Standardization, Geneva, Switzerland, www.iso.ch) An organization that sets international standards, founded in 1946. The U.S. member body is ANSI. 9001 company, dedicated to maintaining the highest quality standards at every level. For a comprehensive document describing the changes in G.IEC, access Coherent's Web Page: http://www.coherent.com - articles directory. CONTACT: Diane McClelland at Coherent +1-730-724-7311 or Georgina Garrett at Garrett Axford +44 (0) 1273-441200 E-mail: dmcclelland@coherent.com |
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