The Public Switched Telephone Network - The public switched telephone network (PSTN) is the international network of circuit-switched telephones. Learn more about PSTN at HowStuffWorks. x
Black Belt Certification. The IASSC Certified Lean Six Sigma Black Belt (ICBB) is a professional who is well versed in the Lean Six Sigma Methodology, who leads improvement projects, typically in a full-time role. A Lean Six Sigma Black Belt possesses a thorough understanding of all aspects within the phases of D-M-A-I-C.
Both Six Sigma processes are executed by Six Sigma Green Belts and Six Sigma Black Belts, and are overseen by Six Sigma Master Black Belts. According to the Six Sigma Academy, Black Belts save companies approximately $230,000 per project and can complete four to six projects per year.