Your phone system. A clear connection.
Connect your PBX, softphone or SIP application to Bird. Keep your call-handling logic, with inbound and outbound calling, caller identity and call records in one workspace.
Follow the connection in both directions.
Keep your PBX or SIP application. Inspect admission, delivery and the final observation at the boundary each system owns.
Not inspected
The telephone connected in this fictional case. Test two-way media and the PBX workflow separately; no codec or failover guarantee follows from the diagram.
The example number points to a trunk with no gateway. Add a gateway, confirm inbound direction and explicitly rebind numbers reset to reject. Reenabling a trunk does not restore those bindings.
No call record in this example admission failure. Inspect source IP, allowed voice-write key and the Digest exchange. Absence from the call log does not prove no attempt.
Inspect the destination or PBX timeout, keep the customer request open and apply the application’s deliberate retry policy.
vcl_sip_example_1042Retain this original identity and reconcile equipment, call records and application state before retrying. No telephone or business completion is inferred.
Select the direction and observation, then inspect the path. Input changes invalidate the previous observation.
Evaluation note
Illustrative outbound path. Observation: Not inspected. Verify two-way media, application outcome and current commercial terms separately.
Test identity, authentication, actual media, keypad interoperability and an application outcome before moving customer traffic.
Fictional example. No calls, audio, workspace changes or business actions are sent.
Read the maintained guide ↗Manage trunks with CLI or MCP, then connect your PBX over SIP. Inspect call records to follow the resulting calls and troubleshoot routing.
Companies that trust Bird across their communications.
Read Bird customer storiesThe connection
How does SIP trunking work?
Your phone system sends a call request to its Bird trunk address. Bird authenticates the request, checks whether the call is allowed and connects the carrier leg. SIP establishes the session; media carries the conversation. Both paths need to work for a successful call.
Keep your application
Use a PBX, a desktop softphone or a SIP-capable application. Read the connection details from the trunk, then match transport, authentication and media settings in your client.
Separate the directions
Outbound calling lets your equipment place calls through Bird. Inbound calling delivers calls from your numbers to the gateways you configure. Turn on and test each direction deliberately.
Control the entry point
Choose who can place calls.
Give each site or application the trunk configuration it needs. Use IP allow lists for known equipment, allowed keys for authenticated clients, or short-lived session credentials for browser and temporary clients. A trunk address on its own grants no calling permission.
- 01
Prepare your identity
Use an eligible Bird number or verify a number you control. The presented caller identity and the destination both participate in the admission checks.
- 02
Enable your markets
Turn on the destination countries you need and review current rates. A country being available is different from your workspace enabling it, and neither guarantees every number will connect.
Operate with evidence
From a failed ring to a useful answer.
Inspect the call’s status, final SIP response and any recorded rejection reason. A credential failure may happen before a call record exists; a destination or capacity refusal belongs to a different part of the path. Diagnose the stage before retrying.
Start with a real test
Place a call to a number your team controls. Check audio in both directions, keypad tones and clean hangup before routing customer traffic.
Keep capacity explicit
Plan concurrent calls and calling rate separately. Compare your workload with the applicable account limits and arrange capacity before a larger launch.
Questions about SIP trunking
Do I need to replace my PBX?
Can one trunk handle incoming and outgoing calls?
Can an AI voice application connect over SIP?
What happens if I disable inbound calling?
Does Bird Voice carry emergency calls?
Explore more with Voice
Related resources
Continue with the documentation, guides and examples for this topic. Resources are in English.
Talk to our Voice team
Connect your first trunk.
Prepare your trunk, caller identity and destinations. Test your PBX or softphone with a number your team controls before moving customer traffic.