PBX — Outbound Dial Rules and Trunk Selection
Overview
Outbound routing determines which trunk(s) are used when an extension dials an external number. Rules are matched by dialed prefix and routed through a prioritized list of trunks.
Route Groups
A Route Group is a named set of trunks in priority order. If the first trunk fails, Asterisk automatically tries the next.
- Go to Call Routing → Route Groups.
- Create a group and add trunks in priority order.
- Enable Failback Routing to fall back to gateway trunks when all primary trunks fail.
Dial Rules (Outbound Routes)
Dial rules map number patterns to route groups:
_1NXXNXXXXXX— 11-digit North American numbers_011.— International (starts with 011)_NXXNXXXXXX— 10-digit US numbers_9.— Strip 9 prefix before sending to carrier
Rules are evaluated in order — the first match wins. Use Prepend / Strip to transform the dialed number before sending to the carrier.
Tenant Outbound Permissions
Each tenant can be restricted to specific dial rule sets (e.g., local only, no international). Configure under Tenants → [Tenant] → Permissions.
Outbound Caller ID
Set at the DID or tenant level. The PBX sends the CID in FROM and PAI headers. Ensure the outbound CID matches a number approved by your carrier (screened CID).
Emergency (911) Routing
Create dedicated dial rules for _911 and _9911 pointing to an E911-capable trunk. Ensure the correct ELIN (Emergency Location Identification Number) is sent as the outbound caller ID for accurate location dispatch.