Not all broadband is equal for VoIP. I set up identical VoIP endpoints on 6 different UK broadband connections and measured call quality over 30 days. The results explain why some offices have perfect calls and others have constant complaints.
The Test
- Same VoIP provider, same codec (Opus), same hardware
- 50 test calls per connection per week (200 total per connection)
- Measured during business hours (9 AM - 5 PM)
- All connections in Greater London area
Results
| Provider | Type | Speed | Avg Latency | Avg Jitter | Packet Loss | Avg MOS |
|---|---|---|---|---|---|---|
| BT Business Broadband | FTTP | 500/75 | 8ms | 2.1ms | 0.01% | 4.5 |
| Virgin Media Business | Cable | 350/35 | 14ms | 8.4ms | 0.15% | 4.2 |
| Zen Internet | FTTP | 300/50 | 6ms | 1.8ms | 0.00% | 4.5 |
| TalkTalk Business | FTTC | 80/20 | 18ms | 12.3ms | 0.28% | 3.9 |
| Sky Broadband (residential) | FTTC | 60/15 | 22ms | 15.8ms | 0.42% | 3.6 |
| Three 5G (fixed wireless) | 5G FWA | 200/30 | 35ms | 24.1ms | 0.78% | 3.4 |
Key Findings
1. Fibre beats everything. BT FTTP and Zen FTTP scored identically (MOS 4.5). Cable (Virgin) was good but had higher jitter. FTTC was acceptable but degraded during peak hours.
2. Upload speed matters more than download. VoIP uses 80 Kbps per call in BOTH directions. Sky's 15 Mbps upload handles 10 concurrent calls comfortably. But during peak evening hours (6-8 PM), Sky's upload dropped to 8 Mbps with increased jitter — and call quality suffered.
3. 5G fixed wireless is NOT ready for business VoIP. Average MOS of 3.4 is below the acceptable threshold (4.0). Jitter spikes of 24ms average (with peaks over 80ms) cause audible quality drops. Fine for one person making occasional calls. Not fine for an office of 20.
4. Business broadband outperforms residential on the same technology. BT Business FTTP vs a residential FTTP connection showed the same speed but business had lower jitter (2.1ms vs 4.8ms) and better peak-hour consistency. The extra cost is worth it.
My Recommendations by Office Size
| Office Size | Recommended Connection | Monthly Cost |
|---|---|---|
| 1-5 users (home office) | Any FTTP (residential fine) | £30-50 |
| 5-15 users | Business FTTC or FTTP | £50-100 |
| 15-50 users | Business FTTP (dedicated) | £100-250 |
| 50+ users | Leased line + backup broadband | £250-500 |
The Budget Play
If you cannot afford business-grade broadband, get the best residential fibre available and configure QoS properly. Residential FTTP with QoS gives you 95% of the quality of a leased line at 10% of the cost.
DialPhone provides a free network readiness assessment for UK businesses — they test your specific connection for VoIP suitability before you commit to a plan.
