For anyone involved in buying and managing telephone systems, this book brings clarity to the confusing array of products and services (like voicemail, interactive voice response, fax-on-demand, T-1, DSL, etc.). The author explains how each technology works, and what its practical applications are, so readers can choose the best systems and services for their needs. The book includes lists of products and vendors, plus sample RFPs (request for proposal) that are easily customized for a particular telecom system or cabling purchase. ;