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

# How Fuse picks a number

> Contact continuity, Randomized Area Code and Closest Local Area Code, the three things that decide which of your numbers a call goes out on.

Once you have more than one number, something has to decide which one each call goes out on.

For **single dialing** you can select a specific number, or use automatic selection. **Parallel dialing** always uses automatic selection, so call volume is distributed across your available numbers.

## Contact continuity comes first

Before applying the automatic mode you selected, Fuse checks whether this contact has been called before. When it can, it reuses the same number from the most recent successful attempt.

This gives the contact a consistent caller ID, and may improve recognition on follow-up calls.

<Note>
  A previous number is **not** reused if it has been released, disabled, blocked by compliance requirements, or has an unsatisfactory [health rating](/dialer/business-registration#number-health). In those cases Fuse moves on to the automatic mode.
</Note>

## The two automatic modes

| Mode                        | How it chooses                                         | Why use it                                                            |
| --------------------------- | ------------------------------------------------------ | --------------------------------------------------------------------- |
| **Randomized Area Code**    | Rotates across your eligible numbers                   | Spreads activity more evenly and reduces overuse of any single number |
| **Closest Local Area Code** | Picks the number geographically closest to the contact | Gives the contact a more familiar, local caller ID                    |

### Randomized Area Code

This mode rotates calls across your eligible numbers. It spreads activity more evenly and reduces overuse of any individual number.

<Note>
  Despite the name, this is a **rotation**, not a completely random pick.
</Note>

### Closest Local Area Code

This mode selects the number geographically closest to the contact, when location information is available.

When location cannot be determined, Fuse works down this order instead:

1. A number matching the contact's phone area code.
2. Any other eligible number, if no area code matches.

The result is a familiar, local caller ID wherever the information supports it.

## Where to go next

<CardGroup cols={2}>
  <Card title="Business registration and number health" icon="shield-halved" href="/dialer/business-registration">
    What makes a number eligible in the first place, and what happens when none of them are.
  </Card>

  <Card title="Your phone numbers" icon="phone" href="/dialer/phone-numbers">
    Renting a number through Fuse, or adding one you already own.
  </Card>
</CardGroup>