ESI Digital & VoIP Phone Systems

The superior communication power that your office needs— today and tomorrow.

Whether you have many outside lines and large numbers of users, or just a handful of each, IVX’s modular, flexible design grows with your business. IVX supports up to 84 phone lines and up to 168 ESI Feature Phones. Thanks to ESI’s intelligent design, the patented, built-in IVX voice mail capability doesn’t subtract from this total. IVX maximizes both call-handling capabilities and voice mail storage. As your communications needs grow, you can easily and inexpensively add lines (including high-capacity broadband), phones, and special options — if and when you need them.


ESI X-Class Phone System ESI IVX X-Class Phone System offers a selection among multiple Digital Feature Phones, cost-effective expansion capabilities, automated attendant, automated call distribution (ACD), and voice mail. Also, these systems boast extensive expandability, with up to 252 call-processing ports and up to 420 hours of voice storage, along with support for T1, ISDN PRI, and TAPI computer/telephony integration (CTI). IP capabilities can be added to IVX X-Class and IVX E-Class, allowing existing customers to benefit from VoIP technology as the need arises.

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ESI X-Class Brochure Adobe PDF Brochure

ESI S-Class Phone System ESI IVX S-Class Phone System gives your small to medium-sized business the power to present your most professional side to your customers. Each IVX phone system says, “Good morning.” It teaches you how to use and program it. It reminds you to change your personal greeting after a trip. And it stands by, ready to assist you whenever you need help.

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ESI S-Class Brochure Adobe PDF Brochure

ESI S-Class Phone System ESI IVX C-Class Phone System ESI builds big-system features into the small-business IVX C-Class. The patented IVX phone system design means all the vital business communications features are built-in — not added-on. Equipped to handle up to six phone lines, 12 digital stations and two analog stations for fax machines or cordless phones, IVX C-Class gives your business a competitive edge.

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ESI C-Class Brochure Adobe PDF Brochure