> ## Documentation Index
> Fetch the complete documentation index at: https://docs.upliftai.org/llms.txt
> Use this file to discover all available pages before exploring further.

# Phone numbers & concurrency

Every account starts with **one line** and **no number of its own**. Both change by email, not by a setting.

## One call at a time

Your account can have **one phone call live at a time**. Inbound and outbound share that one line. There is nothing to set in the portal or the API.

If you need more, email [founders@upliftai.org](mailto:founders@upliftai.org) with your **use case** and **expected call volume**. Limits go into the thousands of lines.

## What happens when you hit it

* **A [direct API call](/api-reference/starting-a-conversation/dispatch-a-call-from-this-assistant)** gets a **429** and nothing is dialed. Wait for the live call to end. Then dial again.
* **A campaign** never gets a 429. A dial that collides with your limit goes back to the queue with a wait, and the attempt counts. Leave the campaign's [`dialing.lines`](/api-reference/campaigns/create-a-campaign) at 1 until your limit is raised.
* **An inbound call** is never turned away for this limit, but it holds your line while it runs.
* **A second call to the same person** gets a **409** with `number_busy`. That is a per-person rule and applies whatever your limit is.

The 429 body:

```json theme={null}
{ "message": "Organization concurrent outbound call limit reached", "statusCode": 429 }
```

## Which number your customer sees

[Outbound calls](/voice-agents/calling/outbound) go out from a **random Pakistani number in our pool**, so a customer may see a different one on each call.

## A number of your own

A **dedicated number** is assigned on request: email [founders@upliftai.org](mailto:founders@upliftai.org) and we set one up within a day. Depending on your setup the same number can take [inbound calls](/voice-agents/calling/inbound) too.