ESI is a privately held corporation with headquarters in Plano, Texas, just outside Dallas. Rapid growth, stable management and innovative technology have characterized ESI since its founding in 1987.

ESI designs and manufactures high-efficiency, low-cost telephone products including the VoiceWorks 16 automated attendant and voice mail system, the PhoneBill call accounting system and, most notably, the IP Series and IVX Series of all-in-one phone systems. These products have earned numerous product awards from industry publications.

In recent years, ESI expanded its manufacturing group into new, larger facilities, made significant additions to its product engineering department and extensively upgraded its design and testing laboratory.

Markets

As an original equipment manufacturer (OEM), ESI has built private-label versions of its products for some of the world's leading brands in telecommunications, including Comdial, Samsung, Executone and Code-a-Phone.

ESI products are used by major companies such as: