Estech Systems, Inc. (ESI) designs and manufactures high-performance phone systems and cloud bservices for businesses and organizations. ESI uses advanced technology to design IP and digital  communications systems that integrate built-in capabilities, advanced features, and highly differentiated applications into flexible products that are easy-to-use and keep employees productive. ESI has sold over 500,000 business communications systems through hundreds of factory-trained Certified Resellers. Founded in 1987, ESI is celebrating 25 years in business as a privately held corporation with headquarters in Plano, Texas. ESI communications systems are protected by various U.S. patents, granted and pending.