Network planning
VoIP PDD calculator & simulator
Build a routing chain from PBX to PSTN and calculate total post-dial delay. Identify when carriers add excessive latency through grey routes or extra hops.
- Hop 1
- Hop 2
- Hop 3
Results
Total PDD
250 ms
| Hop | Delay | Cumulative |
|---|---|---|
| PBX / SBC | 50 ms | 50 ms |
| Tier-1 carrier | 120 ms | 170 ms |
| PSTN gateway | 80 ms | 250 ms |
How it works
Three steps to results
- 01
Build your route
Add hops for PBX, SBC, carriers, and PSTN gateways. Use presets for direct, grey-route, or international LCR paths.
- 02
Set per-hop delay
Enter milliseconds for each node based on your measurements or vendor SLAs. Reorder hops to match your actual routing.
- 03
Read total PDD
See cumulative post-dial delay with a visual breakdown. Ratings flag routes over 800 ms as likely grey-route quality.
FAQ
Frequently asked questions
Common questions about this tool and how it fits into your VoIP security workflow.
Contact support →PDD is the time from when the caller finishes dialing to when they hear ringing. It includes SIP signaling latency across all routing hops — PBX, SBC, carriers, and PSTN gateways.
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