The ESI-100 architecture allows expansion when required. The Base Cabinet and optional “piggybacking” Expansion Cabinet are wall-mountable and require very little space in your phone closet.

System highlights (maximum capacities shown)
Total stations - 192
IP stations - 192
Digital stations - 168
Analog stations - 56
Call-processing ports - 300
Central Office (CO) lines - 84
Digital line cards (T1/PRI) - 3
Voice mail ports - Up to 24
Voice storage (hours) - Up to 600
Station/special-purpose mailboxes - 1,229
Conference ports (16 members/conference) - 24
Built-in automatic call distribution (ACD) - Yes
Shared-office tenanting (tenants) - 4
ESI Presence Management - Optional
VIP applications - Optional
Mirrored Memory Module (M3) backup - Optional
ESI CS 200 Brochure
Plus other ESI Communications Server features:
Both digital and IP-based Standards-based design (including SIP support) ESI’s Verbal User Guide™ Six-level, 100-branch automated attendant Automatic call distribution (ACD) ESI phones Desktop and cordless models Digital and IP ESI options ESI Presence Management™ VIP™ family of applications Optional IP-based features, including Esi-Link (combines up to 100 ESI systems into one)

Extensive phone options -
ESI Digital Feature Phone — 12-Key, 24-Key, 48-Key regular, and 48-Key TAPI. ESI 48-Key IP Feature Phone II — Connects via LAN, WAN, or Internet; provides full ESI feature set via IP, either locally or at remote location; uses industry-standard G.711 and G.726 compression to reduce bandwidth requirements. ESI Cordless Handset — Two sizes each of three models: Digital, [local] IP, and Remote IP; IP models allow Power over Ethernet (PoE) or AC power for your maximum convenience. Standard analog sets