> ## 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.
# Receive calls on a number
> Create an inbound connection so calls that arrive on your number reach an agent.
An inbound connection routes calls that arrive on a number you own to one agent.
For how connections work and where they live, see
[Connect a phone number](/guides/agents/telephony/overview).
## Prerequisites
Before you begin:
* A number from a carrier, in E.164 format (`+15551234567`).
* Admin access to your SLNG organisation. Creating a connection is a dashboard
task, and the **Telephony** section is admin only.
* An agent to answer 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**, switch to the **Inbound** tab,
and click **Add connection**.
Choose **Twilio** to generate a webhook URL. Choose **Manual** to generate
SIP forwarding targets and optionally restrict source addresses.
Give the connection a name you will recognize in the agent picker, such as
`wayne-enterprises-support`. Add the phone numbers that should reach the
agent, one per line or comma-separated, each in E.164 format.
In **Manual** mode you can also set **Allowed addresses** to restrict which
source addresses may send calls to this connection. Leave it empty to accept
calls from any address your carrier uses.
Click **Create connection**. The connection starts as `pending` while
provisioning finishes, then becomes `active`. If it ends in `error`, open
the connection to see the reason. You cannot attach it until it is active.
## Route calls from your carrier
Your carrier must route incoming calls to the connection. A Twilio number sends
an HTTP request to the generated webhook URL. Another carrier forwards calls to
the generated SIP target.
```mermaid theme={null}
graph LR
tw["Your Twilio number"]
car["Any SIP carrier"]
agent["SLNG agent"]
tw -- "TwiML webhook URL" --> agent
car -- "forward to SIP target" --> agent
classDef slng stroke:#fbe566,stroke-width:2.5px;
class agent slng
```
Open the connection's **View setup** and copy the webhook URL. In the Twilio
console, open the number's **Voice configuration**. Under **A call comes
in**, choose **Webhook**, paste the URL, and select **HTTP POST**.
The URL carries a token that identifies the connection, so treat it like a
credential and do not publish it. If the connection shows no webhook URL
yet, it has not finished provisioning.
Open the connection's **View setup** and copy the **Forwarding targets**.
Configure your SIP provider to forward each number to the target listed next
to it.
If you set **Allowed addresses**, they appear here too. Calls from any other
source address are rejected.
## Attach the connection to an agent
An inbound connection belongs to one agent at a time, because a call arriving on
the number has to reach a single destination.
Open the project, go to its **Telephony** section, and pick the connection
under **Inbound calls**. Connections you cannot pick are disabled and marked
**(Unavailable)** with the reason.
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 $SLNG_API_KEY"
```
```json Response expandable theme={null}
{
"inbound": [
{
"id": "3f9c1b4e-5a27-4f8d-9c11-7b2e6d4a8c05",
"name": "wayne-enterprises-support",
"livekit_trunk_id": "ST_b6TUc5Q7bZMD",
"numbers": ["+15551234567"],
"status": "active",
"selectable": true,
"is_current": false,
"unavailable_reason": null
}
],
"outbound": []
}
```
Copy the `id` of a connection where `selectable` is `true`, then set
`sip_inbound_trunk_id` on the agent.
```bash Request theme={null}
curl -X PATCH https://api.agents.slng.ai/v1/agents/$AGENT_ID \
-H "Authorization: Bearer $SLNG_API_KEY" \
-H "Content-Type: application/json" \
-d '{ "sip_inbound_trunk_id": "3f9c1b4e-5a27-4f8d-9c11-7b2e6d4a8c05" }'
```
A successful response returns the updated agent with
`sip_inbound_trunk_id` set to the connection ID. Sending `null` detaches the
connection and leaves it free for another agent.
### When a connection cannot be attached
The dashboard disables unavailable connections. The API returns the reason in
`unavailable_reason`. See
[When a connection cannot be attached](/guides/agents/telephony/overview#when-a-connection-cannot-be-attached).
## Verify inbound calls
Call one of the connection's numbers from another phone. The agent should answer
and use `inbound_greeting` when you have set one. If the call does not reach the
agent, confirm that the connection is `active`, attached to the agent, and using
the carrier settings shown under **View setup**.
## Greet inbound callers differently
With a connection attached, the agent can use `inbound_greeting` instead of its
default `greeting`, so a caller who dials in hears something different from
someone the agent called. Directional greetings need at least one connection
attached, inbound or outbound, and the agent fails to save without one. See
[Create an agent](/guides/get-started/create-a-project/create-agent#update-an-agent)
for the update mechanic.
## Change or replace the credentials
Manual connections authenticate with a SIP username and password, shown under
**View setup**. To change them, open **Edit** and update both values together.
Configure your carrier to use the same pair. Coordinate the change because calls
can fail while the two sides use different credentials.
Twilio inbound connections do not use a SIP username and password. The webhook
URL contains the connection token, and the dashboard cannot rotate that token in
place. If the URL is exposed, contact SLNG support to replace the connection.
Replacing it may briefly interrupt inbound calls.
## Next steps
* [Place calls from an agent](/guides/agents/telephony/outbound) if the agent
also needs to dial out or transfer callers to a person.
* [Watch the calls](/guides/usage-and-billing) as they arrive.