> For a complete page index, fetch https://docs.synthflow.ai/llms.txt. For full documentation content, fetch https://docs.synthflow.ai/llms-full.txt.

# RingEX

> Legacy setup that registers Synthflow as a SIP extension on RingCentral RingEX, kept for existing deployments while it is sunset.

> **Warning**
>
> **This integration is being sunset and is no longer recommended.** The SIP-extension setup relies on RingCentral behavior outside Synthflow's control, so we can no longer guarantee its reliability.
>
> For RingEX, we recommend forwarding your RingEX number over the PSTN to a [Synthflow number](/phone-numbers#buy-a-number) or a [Twilio number](/phone-numbers#bring-your-twilio-numbers). You can also use the native [RingCX integration](/ringcx), or [route calls directly to Synthflow](/route-sip-calls). Talk to your account manager to choose the right path for your setup.

In this legacy setup, Synthflow registers with RingCentral as a generic SIP IP phone (an extension) and answers the calls that reach it. This page stays available for deployments that already use it.

## Limits

* **Maximum 5 concurrent calls per extension.** When all five call slots on an extension are in use, additional inbound callers hear that the number is busy or unavailable.
* **No outbound calling.** RingEX SIP extensions registered through Synthflow cannot place outbound calls.

Warm and cold transfers, over SIP or the PSTN, work as expected.

## RingCentral IP phone

Synthflow connects to RingCentral with the SIP credentials of an IP phone. Get them from the customer's account in the [RingCentral Service Portal](https://service.ringcentral.com/application/company/phoneNumbers/allNumbers). Select an existing generic SIP IP phone, or create one with manual provisioning.

The screenshots below show how to get the IP phone connection details from RingCentral.

![](https://files.readme.io/e175c7a1e71ea550b2ee57b4c206cff369c62d3c96994a42c3408c9d4d6d733d-image.png)

![](https://files.readme.io/7dd9a538d8716dccc85281b6c53b13d796f824642cd6d5725a0fcd4c36c26249-image.png)

Select **Yes**.

![](https://files.readme.io/ba09f6eb56fcd413c6682a05235b44672ec257a32fbede1b9a1bb07df6b2b622-image.png)

Select **Set Up and Provision**.

![](https://files.readme.io/da3db86d6539f6e356706926cf1b9b2f14c24164b57dc1526e12fb7147535747-image.png)

![](https://files.readme.io/5371b9abb73c1fe80bcd526d700b0c9ad40e03e459b0372cd0e741544f7d4a1a-image.png)

Save the connection details for the next steps.

> **Warning**
>
> Copy and paste the SIP details exactly. Imprecise details can get you blocked by RingCentral's anti-flood logic.

![](https://files.readme.io/77d70f3fb4dc12abeab7a5921d3c5740d5a30a34670cb32af0be3cb29722eb56-image.png)

## Synthflow number

On the Synthflow **Phone Numbers** page, add the number to your workspace with the SIP details from RingCentral. The **Termination URI** is your SIP domain on RingCentral.

![](https://files.readme.io/51cb30ff88ab23175e98747bc1cc4eeadf6f19226668e283e1a5a667c27bd616-image.png)

![](https://files.readme.io/7f3e86a8dc0a1282c85d82c6ee88e7d9d6a6765a81a891a9f46f58db3ef85109-image.png)

### Registration Expiry

RingCentral requires Synthflow to register (send `REGISTER` traffic) as a SIP extension. Registration is always on for RingCentral numbers, so there is no checkbox to turn it on.

When you add the number, you can set the **Registration Expiry**: how often, in seconds, Synthflow refreshes the registration with RingCentral. It takes whole numbers from **60** to **3600**. The default is **300** (5 minutes).

## Agent assignment

Create an agent and attach the number to it. The agent must be on version 2.0.

![](https://files.readme.io/a079a66eeb8ca1427559af5cd256a0c1028ad8fbbdd4b6c4050e137a3d995002-image.png)

![](https://files.readme.io/e725fa9c429539dd02c71c2ee71d986615337531f7c9a33f5c2a96eaecd17513-image.png)

![](https://files.readme.io/405e48ef87dc54f3a6c4d20588069671830f76f68a46025671b2fd77bdc6255c-image.png)

![](https://files.readme.io/a1cddb1e9d00cf56ab1fc975d7e32f5313401c757b8ab1a68beeff59d91517ba-image.png)

Synthflow creates the SIP trunk when you attach the number to the agent.

![](https://files.readme.io/5b5de46136cd2b25fa973fa722abd1785f7c84766a38bc35780297fcba6f35b2-image.png)

RingCentral processes the registration in one to two minutes. After that, you can place a test call.

![](https://files.readme.io/ee59e466316ca84513c80406efbd574c00a0ecfae1f9abcc2a6377ae3e67dc2d-image.png)