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

# Queue and limits

> When your calls are dialled, and the guards that protect your contacts and your bill.

Calls are not dialled the instant you create them. Each one joins your account's **call queue**, and Telleo dials it when:

1. one of your **lines is free** (your plan sets how many calls run at the same time);
2. it is inside your **calling hours**; and
3. no **limit** below holds it back.

A single call (`POST /v1/calls`) goes to the front of the queue and is dialled straight away when a line is free. Calls from a [batch](/guides/bulk-calling) wait their turn behind single calls, so a large batch never delays the lead who just filled your form.

While a call waits, it is `queued`. When something is holding it, `status_reason` says what in plain words and `scheduled_for` says when it will be tried next.

## Calling hours

Calls are only dialled inside the calling windows set in your AI calling settings. A call created outside them stays `queued` with `scheduled_for` set to the next window, and goes out then. You do not need to schedule anything yourself.

## Limits

| Guard | What happens |
| - | - |
| **Daily limit for your account** | Calls beyond your account's AI-call limit for the last 24 hours wait (`queued`) until the limit allows more. |
| **Calls per number per day** | A number is called at most 3 times in 24 hours, unless your settings say otherwise. A call over the limit ends `canceled` with the reason *Already called the maximum number of times today.* |
| **Gap between calls to one number** | Two calls to the same number are kept at least an hour apart. A call that comes too soon waits (`queued`) and goes out after the gap. |
| **One waiting call per number** | A number with a call already waiting in the queue cannot get another: `409 call_already_queued`. |
| **Time in the queue** | A call that is still waiting 48 hours after it was created ends `expired`. |
| **Credits** | Without credits, new calls are refused with `402 insufficient_credits`. Calls already queued wait, and resume after a top-up. |

These guards apply to every call made through the API. [Test calls](/concepts/test-mode) skip them.

## Throughput

How fast a batch completes depends on how many lines your plan runs at once and how long conversations last. As a rule of thumb, `lines × 20` calls an hour with three-minute conversations. Ask us to raise the number of lines for large campaigns.


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