That’s because an ESI Communications Server — the ESI-1000, the ESI-600, the ESI-200, or the ESI-100 — can be a traditional digital business phone system, a fully standards-based IP telephony system, or any mix of the two. The choice is entirely yours, and the mix can easily change when your needs do.
Ready to shoulder the load for your business
Each ESI Communications Server combines multiple first-rate, feature-rich systems into one tightly integrated unit:
- Business phone system
- Voice mail
- Automated attendant with six levels and 100 branches
- Messages-on-hold
- Enhanced Caller ID**
- Automatic call distribution (ACD)
- Intelligent Call Forwarding™ †
- Optional Windows-based VIP family of communication management tools
- Optional ESI Presence Management
- Network-based VoIP telephony*
Properly configured by your Certified ESI Reseller, an ESI Communications Server can handle your heaviest communications needs. There are multiple models, with differing capacities, but all share the features mentioned above plus:
- Digital stations, IP stations (including SIP), or any combination thereof
- T1/PRI support
- Massive voice message storage
- Sophisticated voice mail features


