CallTower vs UniVoIP
The advisor verdict
Both are channel-delivered UCaaS specialists: CallTower offers multi-engine options (Cisco, Microsoft Teams, Zoom, CoreXT) at larger scale; UniVoIP is the Microsoft Teams phone specialist with white-glove E911-compliant rollouts for mid-market. Mixed or Cisco-heavy estates → CallTower. All-in on Microsoft Teams → UniVoIP.
At a glance
| CallTower | UniVoIP | |
|---|---|---|
| Starting price (list) | custom (quote-based) | custom (quote-based) |
| Pricing model | Quote-based per-user contracts via channel partners | Quote-based per-user contracts |
| Best segments | Mid-market, Enterprise | Mid-market, Enterprise |
| Founded | 2002 | — |
| Headquarters | Lehi, Utah | El Segundo, California |
CallTower is best for
CallTower suits organizations wanting engine choice (Cisco/Teams/Zoom) with managed global delivery.
UniVoIP is best for
UniVoIP suits Microsoft-centric mid-market rollouts that value Teams-phone depth and managed E911 compliance.
Feature comparison
| Feature | CallTower | UniVoIP |
|---|---|---|
| Cisco-powered UCaaS | ✓ | — |
| Microsoft Teams Phone options | ✓ | — |
| Contact center (UCaaS+CCaaS) | add-on | — |
| Global calling | ✓ | — |
| Managed rollout & 24/7 support | ✓ | — |
| Microsoft Teams Phone enablement | — | ✓ |
| Cisco-powered cloud voice | — | ✓ |
| E911 compliance (Kari's Law/RAY BAUM) | — | ✓ |
| Managed migration | — | ✓ |
| Contact center for Teams | — | add-on |
Feature availability varies by plan tier; full snapshots on the CallTower review and UniVoIP review.
Pros & cons
CallTower
- Multi-engine options (Cisco, Microsoft, Zoom, CoreXT)
- Strong managed service and support reputation
- Global calling and multi-site expertise
- Bundles UC and contact center
- Quote-based pricing with no published rates
- Experience varies by chosen underlying engine
UniVoIP
- Deep Microsoft Teams phone specialization (Operator Connect/direct routing)
- White-glove migrations and ongoing management
- Strong E911 compliance tooling
- Responsive, channel-aligned support
- Microsoft-centric; limited appeal outside that stack
- Quote-based pricing
Our recommendation
Both are channel-delivered UCaaS specialists: CallTower offers multi-engine options (Cisco, Microsoft Teams, Zoom, CoreXT) at larger scale; UniVoIP is the Microsoft Teams phone specialist with white-glove E911-compliant rollouts for mid-market. Mixed or Cisco-heavy estates → CallTower. All-in on Microsoft Teams → UniVoIP.
Comparison is editorial and independent. Pricing references published list rates as of September 2026 and changes frequently. Vendor names are trademarks of their respective owners; The VoIP Advisors is independent and not affiliated with either vendor.