churn zone
 n.— «Ditech Networks, a leading provider of voice quality solutions to the global communications industry, today announced the results of its worldwide voice quality audit, which showed that an average of 39 percent of all mobile calls fall below the industry minimum standard for voice quality, often called the “churn zone.” » —“Audit of 630 Million Live Mobile Calls Shows 39% Fall Below Industry Minimum Standard for Voice Quality” in Mountain View, California PR Newswire Feb/ 6, 2008. (source: Double-Tongued Dictionary)

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