> ## Documentation Index
> Fetch the complete documentation index at: https://docs.slng.ai/llms.txt
> Use this file to discover all available pages before exploring further.
# Place calls from an agent
> Create an outbound connection so an agent can dial out and transfer callers to a person.
An outbound connection gives an agent a caller ID and a route to the phone
network. Without one, [call dispatch](/guides/agents/telephony/dispatch-calls)
fails and the Transfer Call tool has no carrier route. For how connections work
and where they live, see
[Connect a phone number](/guides/agents/telephony/overview).
You can share an outbound connection across multiple agents in the same region.
Create separate connections when agents need different caller ID pools or
carrier routes.
## Prerequisites
Before you begin:
* A SIP trunk with your carrier, and at least one number on it to use as a
caller ID, in E.164 format (`+15551234567`).
* The termination host and SIP credentials for that trunk. In Twilio these live
under Elastic SIP Trunking.
* Admin access to your SLNG organisation. Creating a connection is a dashboard
task, and the **Telephony** section is admin only.
* An agent to place the calls. Keep its ID for the API path. If you do not have
one, see [Create an agent](/guides/get-started/create-a-project/create-agent).
* An SLNG key for the API path. See
[How to set up](/guides/get-started/quickstart).
## Create the connection
In the dashboard sidebar, open **Telephony**, stay on the **Outbound** tab,
and click **Add connection**. Pick **Twilio** for the guided setup or
**Manual** for any other SIP provider.
Fill in four values:
| Field | What to enter |
| ---------------------------- | ----------------------------------------------------------------------------------------------------------------------------------- |
| **Connection name** | A name you will recognize in the agent picker, such as `wayne-enterprises-outbound` |
| **Termination host** | The carrier host that accepts outbound calls, such as `wayne.pstn.twilio.com`. In Twilio, use the host from the Termination SIP URI |
| **Caller ID pool (rotates)** | The E.164 numbers the agent calls from, one per line or comma-separated |
| **Transport** | **Auto**, unless your carrier requires **UDP**, **TCP**, or **TLS** |
Enter the auth username and password your carrier expects. In Twilio mode
you can click **Generate credentials** to have SLNG produce a pair, then add
that pair to Twilio in the next step.
Passwords must contain at least one uppercase letter, which is a Twilio
requirement rather than an SLNG one.
In **Twilio** mode the last step is a checklist to complete in the Twilio
console:
* **Credentials List**: add the username and password from the previous step.
* **Termination**: confirm the termination host matches what you entered.
* **Numbers**: confirm your Twilio number is attached to the trunk.
In **Manual** mode there is no checklist. Configure the carrier to accept
calls authenticated with the credentials you entered.
A new connection starts as `pending`, then becomes `active`. If it ends in
`error`, the connection shows the reason. You cannot attach a connection to
an agent until it is active.
## How the caller ID is chosen
An outbound connection can hold more than one number. The caller ID is selected
at random from this pool for each call. Edit the connection to add or remove
numbers.
The caller ID always comes from this pool. A dispatch request sets the
destination number, so give a campaign that needs a specific caller ID its own
connection.
## Attach the connection to an agent
Open the project, go to its **Telephony** section, and pick the connection
under **Outbound calls**. You can pick the same connection for multiple
agents in the same region.
List the connections available to the agent.
```bash Request theme={null}
curl https://api.agents.slng.ai/v1/agents/$AGENT_ID/sip-trunk-options \
-H "Authorization: Bearer $SLNG_API_KEY"
```
```json Response expandable theme={null}
{
"inbound": [],
"outbound": [
{
"id": "8d2a7c60-19be-4e35-a4f7-0c53f1b9e2d4",
"name": "wayne-enterprises-outbound",
"livekit_trunk_id": "ST_a8Jk3mP2wQ9R",
"numbers": ["+15551234567"],
"status": "active",
"selectable": true,
"is_current": false,
"unavailable_reason": null
}
]
}
```
Copy the `id` of a connection where `selectable` is `true`, then set
`sip_outbound_trunk_id` on the agent.
```bash Request theme={null}
curl -X PATCH https://api.agents.slng.ai/v1/agents/$AGENT_ID \
-H "Authorization: Bearer $SLNG_API_KEY" \
-H "Content-Type: application/json" \
-d '{ "sip_outbound_trunk_id": "8d2a7c60-19be-4e35-a4f7-0c53f1b9e2d4" }'
```
A successful response returns the updated agent with
`sip_outbound_trunk_id` set to the connection ID. Sending `null` detaches the
connection.
If a connection shows as **(Unavailable)** in the picker, it cannot be attached
yet. See
[When a connection cannot be attached](/guides/agents/telephony/overview#when-a-connection-cannot-be-attached).
## Verify outbound calls
Use [Dispatch outbound calls](/guides/agents/telephony/dispatch-calls) to call a
number you can answer. Confirm that the phone rings, the caller ID belongs to the
connection's pool, and the agent uses `outbound_greeting` when you have set one.
If the call fails, confirm that the connection is `active`, attached to the
agent, and configured with credentials that your carrier accepts.
## What an outbound connection is required for
With one attached, the agent can:
* Be dispatched on a call. See
[Dispatch outbound calls](/guides/agents/telephony/dispatch-calls).
* Use `outbound_greeting`, so a person the agent called hears a different
opening line than someone who dialled in. Directional greetings need at least
one connection attached, and the agent fails to save without one.
* Use the Transfer Call tool, which places an outbound call to reach a person.
## Rotate the credentials
For a Twilio connection, keep the old credentials in Twilio until you verify the
new pair:
In the **Telephony** section, open **Rotate creds**, then click **Generate
credentials**. Copy the new username and password.
Add the new pair to the trunk's **Credentials List**. Do not remove the old
pair yet.
Return to the dashboard and click **Activate**. The connection starts using
the new pair immediately.
Place a test call and confirm that it connects. You can then remove the old
pair from Twilio.
For a manual connection, open **Edit** and update the username and password to
match the pair configured by your carrier. Coordinate the change because calls
can fail while the two sides use different credentials.
## Next steps
* [Dispatch outbound calls](/guides/agents/telephony/dispatch-calls) to place
the first one.
* [Receive calls on a number](/guides/agents/telephony/inbound) if callers also
dial the agent.