> Source: https://docs.virtuo.in/vio/telephony
> How Vio phone numbers work: a number can answer inbound calls, place outbound calls, or both. Import a Twilio number or bring your own carrier.

# Phone numbers & calls

**In Vio, a phone number is the bridge between your caller and your agent. Every number can do one or both of two jobs: answer incoming calls (inbound) and place outgoing calls (outbound).** You get a number in one of two ways — import a number you own on **Twilio**, or bring your own carrier over a SIP trunk.

## Inbound vs outbound — the one thing to understand

A number in Vio has a **direction**, and the two directions are independent:

| Direction | What it means | Who talks |
|---|---|---|
| **Inbound** | Your number **answers** calls that people make to it. | The assigned agent picks up; if none is assigned, your workspace's **default agent** answers. |
| **Outbound** | Vio **places** calls from the number — on your behalf. | The agent dials out for a campaign, or a scheduled callback fires. |
| **Both** | The same number answers and dials. | Most production numbers end up here. |

You do not have to choose one forever. A number can start inbound-only and have outbound switched on later.

<Callout type="info">
**No agent assigned? Your default agent answers.** Set a workspace default so an unassigned number is never a dead line. You assign a specific agent per number in the **Numbers** view — see [**Phone numbers**](/vio/telephony/numbers).
</Callout>

## Two ways to get a number

- **Import a Twilio number** — the fastest path. Bring a number you already own on Twilio; inbound reaches your agent immediately, and one click enables outbound through Twilio's Elastic SIP Trunk. See [**Phone numbers**](/vio/telephony/numbers).
- **Bring your own carrier (BYOC)** — point your existing carrier or PBX (for example **FreePBX**) at Vio over a SIP trunk, and keep your own numbers and carrier rates. See [**SIP trunks (BYOC)**](/vio/telephony/sip-trunks).

New to this? Start at [**Connect a number**](/vio/getting-started/connect-a-number) for the guided setup, then come back here for depth.

## Explore telephony

<FeatureGrid>
  <FeatureCard
    href="/vio/telephony/numbers"
    title="Phone numbers"
    description="Import a Twilio number, assign the agent that answers it, and switch on outbound per number."
    icon="plug"
    cta="Manage numbers"
  />
  <FeatureCard
    href="/vio/telephony/sip-trunks"
    title="SIP trunks (BYOC)"
    description="Connect your own carrier or PBX so calls flow through Vio while you keep your numbers and rates."
    icon="stack"
    cta="Connect a carrier"
  />
  <FeatureCard
    href="/vio/telephony/outbound-campaigns"
    title="Outbound campaigns"
    description="Upload a contacts list and let the dialer call it for you — paced, retried, and analysed by AI."
    icon="rocket"
    cta="Launch a campaign"
  />
  <FeatureCard
    href="/vio/telephony/callbacks"
    title="Callbacks"
    description="Follow-up calls your agent booked itself mid-conversation, auto-dialled at the scheduled time."
    icon="bolt"
    cta="See callbacks"
  />
</FeatureGrid>

## Frequently asked

**Q. Can one number both answer and place calls?**
Yes. Direction is a property you switch on. A number can be inbound-only, outbound-only, or both. Most businesses run their main line as **both** so the same identity answers customers and dials them back.

**Q. What happens if a call comes in and no agent is assigned to the number?**
Your workspace's **default agent** answers, so the line is never dead. Assign a specific agent to a number when you want a different persona or script for that line — for example a sales line versus a support line.

**Q. Do I need Twilio to use Vio?**
No. Twilio is the quickest way to get live, but you can bring your own carrier over a SIP trunk instead and keep your existing numbers and per-minute rates. See [**SIP trunks (BYOC)**](/vio/telephony/sip-trunks).

## Next step

Once your number is live, every call it handles lands in the [**Call logs**](/vio/call-logs) with a transcript, recording, AI summary, and per-call cost.