Elastic SIP Trunking calls to US and Canadian destinations are billed by zones. Here's a breakdown of how it works:
- Zone Definition: Each zone represents a collection of area codes and prefixes (NPA-NXX) where we charge the same rate. This segmentation allows Twilio to offer more competitive rates for each zone.
- Zone 1: The vast majority of calls, well over 90% of Twilio’s overall calls, fall into Zone 1. This zone includes the most common area codes and prefixes.
- Rate Deck: For a specific list of prefixes and zones, you can refer to the downloadable CSV rate deck available at Twilio's SIP Trunking Termination Pricing.
By segmenting destinations into zones, Twilio ensures that customers receive competitive pricing tailored to their specific calling needs.