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

# DID Forwarding

> Point an existing phone number at SmartAlex using call forwarding. No SIP trunk, no PBX changes, live in minutes.

<Info>
  **Audience**: whoever administers your phone number or hosted PBX. **Time**: 5 to 10 minutes. **Works with**: any carrier or hosted platform that can forward a number, including RingCentral, 8x8, GoTo, Dialpad, and traditional telco lines.
</Info>

## What it is

DID forwarding is the simplest way to put the AI on a phone number. Instead of connecting a SIP trunk between your phone system and SmartAlex, you keep your number exactly where it lives today and set it to **forward** to a SmartAlex number.

A DID is just a phone number (the industry term is Direct Inward Dialling). When a caller dials your published number, your carrier or hosted PBX immediately forwards the call to the SmartAlex number behind it, and the voice engine answers. Your callers never see the forwarding number. They dial the number on your website and the AI picks up.

Nothing about your account with your carrier or PBX changes. You are using the same call-forwarding feature you would use to send calls to a mobile or an answering service, pointed at us instead.

## When to use it

<CardGroup cols={2}>
  <Card title="Hosted PBX platforms">
    Cloud phone systems like RingCentral, 8x8, GoTo, and Dialpad do not always expose a generic outbound SIP trunk on every plan. Every one of them can forward a number, so DID forwarding works no matter which plan you are on.
  </Card>

  <Card title="A quick start or pilot">
    You want the AI answering a real number this afternoon without touching PBX config, opening firewall ports, or filing a support ticket with your carrier. Forward the number, test, done. You can graduate to a SIP trunk later.
  </Card>

  <Card title="Overflow and after-hours">
    Forward a number only when your team is closed, or only when a queue overflows, and let the AI catch what would otherwise hit voicemail. Your PBX decides when to forward.
  </Card>

  <Card title="No PBX at all">
    You have a plain telco number with no phone system behind it. Set conditional or unconditional forwarding in your carrier portal and the AI answers.
  </Card>
</CardGroup>

## How it compares to a SIP trunk

Both approaches get the AI answering your calls. They differ in where the wiring lives and how much control you keep.

|                            | DID forwarding                                            | SIP trunk                                                          |
| -------------------------- | --------------------------------------------------------- | ------------------------------------------------------------------ |
| Setup effort               | Toggle one forwarding rule                                | Create a trunk both sides, match codecs                            |
| PBX changes                | None                                                      | New trunk, DID routing, firewall rules                             |
| Time to live               | Minutes                                                   | 10 to 45 minutes                                                   |
| Transfers to a human       | Voice engine dials the target number and bridges the call | Handed straight back to your PBX over the same trunk via SIP REFER |
| Caller ID to the extension | Depends on your carrier or PBX forwarding behaviour       | Preserved end to end                                               |
| Concurrent-call control    | Governed by your forwarding number's capacity             | Set explicitly on the trunk                                        |
| Best for                   | Hosted PBXes, pilots, overflow, plain numbers             | Long-term production on an on-premise or trunk-capable PBX         |

<Note>
  The one thing to check up front is **caller ID passthrough**. When a call is forwarded, some carriers and hosted PBXes pass the original caller's number through and some replace it with the forwarding line's number. If your agent needs the real caller ID (for lookups, logging, or callbacks), confirm your platform forwards the original CLI, or move to a SIP trunk where caller ID is preserved end to end.
</Note>

## The flow

```mermaid theme={null}
flowchart LR
  A["Caller dials your published number"] --> B["Your carrier or hosted PBX"]
  B -->|"Call forward"| C["SmartAlex number"]
  C --> D["The voice engine answers"]
  D -->|"Transfer to a human"| E["Voice engine dials the target"]
  E --> F["Extension or mobile rings"]
```

Because there is no trunk back into your phone system, a transfer to a human is the voice engine placing a fresh outbound call to a phone number (a mobile, or an extension reachable on a public DID) and bridging the caller to it. If you need transfers to ring an internal extension directly over SIP, use a SIP trunk instead.

## Setup outline

<Steps>
  <Step title="Provision a SmartAlex number">
    In the dashboard, go to **Phone Numbers**, then **Buy Number** (or **Import Your Number** if you already own one you want us to host). Pick the country and area code, and assign it to the agent that should answer. This is the number you will forward to. It stays private, your callers never dial it directly.
  </Step>

  <Step title="Turn on forwarding at your carrier or PBX">
    In your carrier portal or hosted PBX admin, find the number your customers actually dial and set its call-forwarding destination to the SmartAlex number from step 1.

    * **Plain telco number**: set unconditional (or conditional) call forwarding to the SmartAlex number.
    * **Hosted PBX, single user or number**: open the user or number, then **Call Handling and Forwarding**, and forward to the SmartAlex number.
    * **Hosted PBX, queue or auto-attendant**: set the overflow, no-answer, or after-hours destination to the SmartAlex number so the AI catches those calls.
  </Step>

  <Step title="Add transfer contacts in SmartAlex (optional)">
    If the AI should be able to hand callers to a human, open the agent and add the people or departments it can reach, each as a reachable phone number (a direct dial, a mobile, or an extension exposed on a public DID). Give each a display name and free-form aliases so the AI matches a request like "put me through to accounts" without you scripting every phrasing.
  </Step>

  <Step title="Link the agent">
    In **Agent Studio**, open your agent, go to the **Telephony** tab, and confirm the SmartAlex number is assigned to it. Save. The next inbound call will reach this agent.
  </Step>

  <Step title="Test the number">
    From a mobile, dial your **published** number (not the SmartAlex one). Your carrier forwards it, and the AI should answer within a second or two. If you configured transfers, ask to be put through and confirm the target rings.
  </Step>
</Steps>

## Things to know

<AccordionGroup>
  <Accordion title="Will my callers ever see the forwarding number?">
    No. Callers dial your published number and hear the AI answer. The SmartAlex number sits behind the forward and is never shown to them.
  </Accordion>

  <Accordion title="Does this appear in my carrier or PBX call logs?">
    Yes. Forwarded calls show in your carrier or PBX records as forwarded to an external number, exactly like forwarding to a mobile. SmartAlex keeps its own detailed call records with transcript, outcome, and recording independent of your platform.
  </Accordion>

  <Accordion title="Can I forward only some of the time?">
    Yes, and this is a common setup. Use your platform's conditional forwarding: after hours, on no answer, or on queue overflow. The AI only picks up the calls you route to it, and everything else stays on your normal routing.
  </Accordion>

  <Accordion title="What about concurrent calls?">
    Your forwarding line's capacity governs how many calls can be forwarded at once. If you expect high concurrency, confirm your carrier or PBX allows enough simultaneous forwarded legs, or move to a SIP trunk where you set the concurrent-call limit explicitly.
  </Accordion>

  <Accordion title="Can I switch to a SIP trunk later?">
    Yes. DID forwarding and SIP trunks coexist on the same account. A common path is to start with forwarding for a pilot, then move the number onto a trunk once you want caller ID preserved end to end and transfers handed straight back to your PBX. Nothing you set up here is wasted.
  </Accordion>
</AccordionGroup>

## Next steps

<CardGroup cols={3}>
  <Card title="Connection modes" href="/telephony/connection-modes">
    Compare DID forwarding, inbound SIP trunk, and native extension mode, and pick the right one.
  </Card>

  <Card title="RingCentral" href="/telephony/ringcentral">
    The full forwarding walkthrough for a RingCentral account.
  </Card>

  <Card title="Troubleshooting" href="/telephony/troubleshooting">
    If the forward does not reach the AI, start here.
  </Card>
</CardGroup>