***

title: SIP integration with Telnyx
slug: sip-with-telnyx
---------------------

For clean Markdown of any page, append .md to the page URL. For a complete documentation index, see https://docs.synthflow.ai/llms.txt. For full documentation content, see https://docs.synthflow.ai/llms-full.txt.

<Note>
  **Note**: SIP trunking is only available on the Synthflow Enterprise Plan.
</Note>

***

### 1. Setup Telnyx

* **Step #1: Create the SIP trunk:** Create the trunk, select FQDN as the type, and give it a name.
  * ![](https://files.readme.io/f7a3ff684461182ef964424921331785d88abd4a8332b5e4341d3c0edddfb343-image.png)
* **Step #2: Add FQDN & Add the FQDN of Synthflow's SIP server:**
  * Select `A` as the DNS record type.

  * Enter `sip.synthflow.ai` in the FQDN field.

  * Enter `32681` in the Port field.

  * ![](https://files.readme.io/d63f112b57b704703b76ec7ea28cda168f0e38ee4ef44b9c161ef4fe3beeb5ae-image.png)

    ![](https://files.buildwithfern.com/synthflow.docs.buildwithfern.com/64ba2032aeb6db9fe07ec0c91a04f2532846ab3697fe0ef3ba233d3968f5b142/docs/assets/screenshots/telnyx-add-fqdn-modal.png)

    <br />

  * \*\*Step #3:  Setup Authentication for Outbound Calls:\*\*Select credentials as the authentication method, and add the username and password. You will need to use this username and password when importing the number to Synthflow

    * ![](https://files.readme.io/2234ea6dc96e82a1abcbf855ae6ca139a8b6c0f8d56df8914bfcc3544822ab33-image.png)
* **Step #4: Setup Settings for Inbound:** Select `+E164` as the number format. Select `G711`and `OPUS` as the codec.

  * ![](https://files.readme.io/f5b83df34992ffd30378dc89eb088b0c0776f07a4e72c3cb83ecce2bfd2d7e57-image.png)

![](https://files.readme.io/15f6d830193ceffdd4bc53e202ad47012aeaeae140fea063adbe98914454e3d9-image.png)

<br />

**Step #5: Settings for Outbound:** Create an Outbound Voice Profile. Select your `SIP region`.

* * ![](https://files.readme.io/6496405e7f740f46d6c0fc06c45f17a8eebc266fc2c130a69b3205fd1e527c9a-image.png)

    ![](https://files.readme.io/5205a046f8f1aa7d04665ce9313cc6b79dbaa940f81c287bbdee5b8ecc1a7e91-image.png)

    ![](https://files.readme.io/77006fa3eb5d7a8775c08a44474ffec7748725da5ec8189228854f5d5f392e5b-image.png)

    Go back to the new SIP trunk you've created, select the Outbound tab, and now Select the new voice Profile you have created

    * ![](https://files.readme.io/ae29d6fe2f32528e3dd547807be23a477ea1af21c79c45b5bfb36394a4867ca9-image.png)
* **Step #6: Add numbers to the SIP Trunk:** You've created the SIP trunk, now you would need to purchase numbers / move existing numbers to this trunk.

  * ![](https://files.readme.io/8f8f918625529e4628dee3aed4904d85c04ea66093ee79d1877213c949586367-image.png)

    ![](https://files.readme.io/c06039422560773bd7c320a4333ad0df6dd9056914f2d76ec416bd2a141fc64c-image.png)

<br />

### 2. Import Numbers to Synthflow\.ai

Now that the number is set up with your SIP trunking, you need to **import the number to Synthflow\.ai** so that we will know how to route the call.

![](https://files.readme.io/34dffa668dc7381fd822616bcfaccdeaa27ec998c25c6edf224d9c231a32296e-image.png)

* Here, you will supply the **termination SIP URI**which is `sip.telnyx.com`
* You will need to supply the **username and password** as well.

![](https://files.readme.io/b4aba0a64cfc305c0dc056792d8226f939ffeb02f13c57e43db4b160bcb4ff26-image.png)

<br />

Once the number is imported, you can make and receive calls with this number just like a number you purchased from **Synthflow\.ai**.

If you wish for **Synthflow\.ai** to stop using this number, you can delete it from the dashboard or via the **Delete Number API**.