Make outbound calls through a SIP trunk

​

Before you begin

• The trunk has at least one gateway and one number. See Connect your carrier.
• Your carrier accepts calls from Bolna: it allowlists 15.252.21.46 and 13.206.230.198, or the trunk has the carrier credentials it issued.
• The trunk is enabled. A disabled trunk places no calls.

​

Switch the agent to the trunk

1

Set the telephony provider

Open the agent and go to the Calling tab. Under Call Configuration, set Telephony Provider to SIP Trunk. The option appears once your account has a trunk. If your account also has a legacy SIP trunk, that one is listed as SIP Trunk (previous).

2

Place a call

Open the agent’s outbound call dialog. The caller ID list reads Select a phone number; pick one of your trunk numbers. Enter the number to call and click Place call. A SIP Trunk agent always needs a trunk number as its caller ID, so the dialog does not offer Bolna’s shared number.

​

How the call goes out

1. Bolna queues the call. Each trunk has its own place in the queue, and a call leaves it only when the trunk has a free channel. When every channel is busy, calls wait instead of failing, and one busy trunk does not hold up calls on another.
2. Bolna sends the INVITE to the trunk’s gateways in priority order. A gateway that times out, answers 408 or 478, or answers with a 5xx is skipped for the next one.
3. The phone rings for up to 60 seconds. A busy line or no answer ends the call as busy or no-answer.
4. Once answered, the agent talks until the call ends or reaches the agent’s maximum call duration.

​

Using the API

curl -X PATCH https://api.bolna.ai/v2/agent/<agent_id> \
  -H "Authorization: Bearer <api_key>" \
  -H "Content-Type: application/json" \
  -d '{
    "agent_config": {
      "telephony_provider": "trunk"
    }
  }'

curl -X POST https://api.bolna.ai/call \
  -H "Authorization: Bearer <api_key>" \
  -H "Content-Type: application/json" \
  -d '{
    "agent_id": "<agent_id>",
    "recipient_phone_number": "+919876543210",
    "from_phone_number": "+918045678901",
    "user_data": {
      "customer_name": "Asha"
    }
  }'

{
  "message": "done",
  "status": "queued",
  "execution_id": "b7140255-af33-4608-8e97-04dd944b8e48"
}

​

When a call fails

​

Next steps