Free migration: Switching from ESI? We handle the port, dial plan rebuild, and rehome your phones at no charge. Talk to us

What's happening to ESI.

Estech Systems — the Texas-based ESI — was acquired by UK-headquartered Tollring in 2020. The combined company refocused on the cloud-first eCloud PBX product and, increasingly, on Microsoft Teams calling integrations. The legacy ESI-50, 100, 200, 600, and 1000 hybrid IP-PBXs that dominated US small-business installs through the 2010s have been de-emphasized — still supported, but clearly not where the roadmap is heading.

The dealer channel reacted accordingly. A meaningful share of long-time ESI resellers either reduced their ESI focus or shifted their primary recommendation to another cloud platform — often after watching the cadence of new features and certifications slow on the legacy hybrid line. ESI System Programmer (the config tool for legacy hybrid systems) is still used, but fresh installs and certifications around it are getting rarer.

If you're on the eSIP Evolution Series or an ESI Communications Server, you're on a more modern, SIP-native platform — but the same channel dynamics apply. The right move for most ESI customers is to plan the exit on their schedule while everything is still operational, rather than wait for a forced migration to eCloud or a partner-handoff scramble down the road.

ESI systems we migrate every week.

If you're running one of these, we have a playbook for your migration.

ESI-50
The small-office hybrid IP-PBX, around 4×8×8 base capacity. Common at small professional offices and clinics. Legacy hybrid line — de-emphasized post-acquisition.
ESI-100 / ESI-200
Mid-range hybrid IP-PBXs. The most common ESI systems we still see in field service across small-to-mid US businesses.
ESI-600 / ESI-1000
The larger hybrid platforms with multi-site Esi-Link networking. Used by mid-sized organizations and regional multi-location businesses.
ESI eSIP Evolution Series
The SIP-native ESI platform — the bridge product between the hybrid line and full cloud. Easier to migrate than the hybrid systems because most extensions are already SIP.
ESI Communications Server
The software/appliance ESI Communications Server platform. SIP-native, network-friendly. Migrates cleanly because the trunk and station model is standards-based.
ESI Feature Phones and ePhone-9 IP phones
The 24/48/60-Key Feature Phones are proprietary and don't survive the move. Some ePhone-9 SIP phones can be reflashed for generic SIP and reused with voip.army — we'll evaluate yours.

How an ESI migration works.

Step-by-step. No surprises. Your existing ESI stays operational the entire time.

01

We audit your current ESI setup

Send us a screenshot of ESI System Programmer (legacy hybrid) or your eSIP Evolution / Communications Server admin console. Tell us the model, station count, trunk type, and which features (Esi-Link, Esi-Mail, ACD) you actually use.

02

We mirror your dial plan and routing

Auto-attendant trees, departments, hunt patterns, time-of-day routing, Esi-Mail voicemail boxes, and Esi-Link multi-site routing — we rebuild it all in voip.army before the cutover.

03

We port your numbers

Every DID and trunk number currently on your ESI system ports to voip.army for free. The cutover is sub-5-second — no calls lost.

04

We rehome or replace your handsets

Some ESI ePhone-9 series IP phones can be reflashed for voip.army — we'll evaluate yours and attempt where firmware cooperates. The ESI 24/48/60-Key Feature Phones don't survive the move; we quote Yealink or Grandstream replacements at cost. Many teams skip desk phones entirely and use our mobile/desktop apps.

05

We turn off the ESI

Decommission the ESI-50/100/200/600/1000, eSIP Evolution, or Communications Server. Stop paying your reseller for break-fix. Recycle the equipment.

An ESI customer, after.

★★★★★

"Our accounting firm ran an ESI-200 with about 28 extensions and the Esi-Mail voicemail integrated to email. Our long-time reseller had been quietly pushing us toward eCloud for a couple of years and the pricing kept creeping up. voip.army migrated us in just over two weeks, rebuilt our department routing exactly, and got us on Yealink T54s. We're paying about $580 less a month than the renewed ESI quote and the call quality on residential WiFi is noticeably better."

SC
Stephanie Chen, CPA
Managing Partner, Chen Lambert CPAs · Raleigh, NC

ESI migration FAQ.

The questions we get from ESI customers considering the move. If yours isn't here, ask.

Talk to migration team
Mixed. Some ESI ePhone-9 series IP phones can be reflashed to generic SIP firmware and registered to voip.army — we've done it successfully on a number of jobs, though the process is not always clean. The proprietary ESI 24-Key, 48-Key, and 60-Key Feature Phones used on most ESI-50/100/200/600 hybrid systems are tightly bound to the ESI controller and cannot be repurposed. In practice, most ESI migrations include replacing the desk phones at cost.
A small ESI-50 or ESI-100 site (under 20 users) takes 1–2 weeks end to end including porting. A mid-sized ESI-200 or ESI-600 deployment is 2–4 weeks. ESI-1000 multi-site installs run 3–5 weeks. The eSIP Evolution Series and Communications Server migrations are simpler since they're SIP-native — typically 1–3 weeks. Your existing ESI stays operational throughout.
We rebuild your dial plan in voip.army from scratch — auto-attendant trees, departments, hunt patterns, time-of-day routing, and Esi-Mail voicemail boxes. We work from your ESI System Programmer screens or a printed dial plan. Esi-Link site-to-site routing maps cleanly to voip.army's multi-location features. Day-one feels identical to your callers.
Historical Esi-Mail voicemails and any ESI call recordings stay on the ESI hardware — we don't migrate the audio. If specific messages matter, retrieve them via Esi-Mail Reach or the local CF card before decommission. Going forward, voip.army delivers voicemail to email with audio attachments and AI transcripts, and records calls to encrypted storage (90 days standard, 7 years on Pro).
No. Whatever you're paying — to ESI/Tollring's eCloud channel or a local ESI reseller for break-fix on the legacy hybrid — leave it in place during the migration. Cancel only after voip.army has been live and stable for 2 weeks.

Ready to retire the ESI?

30-day free trial. Free migration assistance from a team that's done this hundreds of times. Your ESI stays running the entire time — no risky big-bang cutover.

✓ Free migration assistance ✓ Free number porting ✓ Phones rehomed where possible ✓ 30-day money-back guarantee