# Configuring webRTC client SIMPL5
## PBX Configuration
To ensure the proper functioning of WebRTC in most browsers, a trusted SSL certificate is required. We recommend using the additional module [Let's Encrypt Module](https://docs.mikopbx.com/mikopbx/english/modules/miko/module-get-ssl-lets-encrypt). For the module to work, the PBX must be accessible via a public IP address.
1. Create a new employee [**account**](https://docs.mikopbx.com/mikopbx/english/manual/telephony/extensions).
2. **Option 1.** For each internal number, set it to work only over the RTC protocol. In the "**Advanced Settings**" section - "**Extra options**", add the following options:
```
[endpoint]
webrtc=yes
```
Click "**Save**". From this moment, this internal number will work *only* using the WebRTC protocol.
Extra options in employee settings
\
**Option 2.** Set up all internal numbers to work *both via PJSIP and WebRTC protocols.*\
To do this, go to **System → General Settings → SIP** and enable the "**Use WebRTC**" toggle switch.
Switch "Use WebRTC"
3. In MikoPBX, go to **Network & Firewall** → **Firewall**, and add the subnet 0.0.0.0 with a mask of 0.0.0.0. Enable access via AJAM.
Address, mask, AJAM switch in firewall settings
4. Go to **System** → **General Settings** → **AMI & AJAM**. Ensure the "**AJAM Port with Encryption**" is set to **8089.**
Encrypted AJAM port
5. In the [**General Settings**](https://docs.mikopbx.com/mikopbx/english/manual/system/general-settings) section, specify the STUN server address. For example, **stun.sipnet.ru**.
Stun server
6. Open the link in your browser: [**https://PBX\_ADDRESS:8089/asterisk/ws**](https://xn--_-7sbbof9dici:8089/asterisk/ws). Use Chrome, as other browsers may have issues. If the certificate is self-signed, you might see a warning "**Connection is not secure**", ignore it and click "**Proceed to the website**."
You should see the following message:
If Asterisk responds, the setup was successful.
## WebRTC Client Setup
1. Go to the website [https://sipml5.org](https://sipml5.org/). You will be redirected to . Follow the link "[Enjoy our live demo](https://www.doubango.org/sipml5/call.htm?svn=252)".
2. Set up the WebRTC client:
In the "**Public Identity**" field, enter the following template:
```
sip:INTERNAL_NUMBER@PBX_ADDRESS
```
**When you enable** the [Use WebRTC](https://docs.mikopbx.com/mikopbx/english/manual/system/general-settings#sip) option
```
sip:INTERNAL_NUMBER-WS@PBX_ADDRESS
```
Click on the "**Expert mode?**" button and proceed with the additional configuration:
In the **"WebSocket Server URL"** field, enter the following format:
