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Extensions and WebRTC

An extension is an employee's internal endpoint inside 4phone. You can route DIDs to it, assign it to call queues, target it from IVR menus, connect it to the browser softphone via WebRTC, and register it on an external SIP device or desktop softphone.

When You Need an Extension​

An extension is needed in almost every case where an employee:

  1. receives incoming calls directly;
  2. participates in a call queue;
  3. uses the browser-based softphone;
  4. needs to receive call transfers from an IVR or another routing scenario.

What Is Configured in the Extension Card​

Typically, you configure:

  1. the extension number itself;
  2. the display name;
  3. the SIP and WebRTC password;
  4. the assigned employee;
  5. whether the extension is active;
  6. WebRTC access;
  7. call recording;
  8. voicemail.

How WebRTC Works​

When WebRTC is enabled on an extension and the extension is assigned to the logged-in employee, the browser softphone can connect and handle calls immediately.

Check

The browser softphone only works with your own assigned extension. If an extension is assigned to another employee, you will not be able to connect to it.

How an Extension's SIP Address Is Structured​

In 4phone, an extension exists within your company's tenant SIP domain. A complete SIP address looks like this:

101@my-company.sip.4phone.uz

Where:

  1. 101 is the extension number;
  2. my-company.sip.4phone.uz is your tenant's unique SIP domain;
  3. sip.4phone.uz is the platform's shared SIP server.
Important

Different companies can use the same extension numbers without any conflict. For example, 101@company-a.sip.4phone.uz and 101@company-b.sip.4phone.uz are completely isolated by their tenant domains.

How to Connect an External Softphone or IP Phone​

If an employee uses a desktop/mobile SIP app or a hardware IP phone instead of the browser, register the extension using these parameters:

  1. SIP Server: sip.4phone.uz
  2. Domain / Realm: <tenant-domain>.sip.4phone.uz
  3. Username / Login / Auth ID: the extension number itself, for example 101
  4. SIP URI: 101@<tenant-domain>.sip.4phone.uz
  5. Password: the extension password
  6. SIP UDP or TCP Port: 5060
  7. SIP TLS Port: 5061
  8. Browser WebSocket: wss://sip.4phone.uz:7443

Auto-Provisioning IP Phones​

If you use hardware IP phones, 4phone can provision them automatically. Three device families are supported:

  1. Panasonic KX-TGP600 -- DECT base station provisioned via Standard File URL and Master File URL;
  2. Yealink T3/T4/T5 -- desktop IP phones provisioned via Server URL;
  3. Grandstream GRP26xx -- desktop IP phones provisioned via Config Server Path.

How It Works​

  1. An administrator creates a device profile under Phone Auto-Provisioning, selects the model, and links an extension.
  2. The system generates a unique provisioning token and URLs.
  3. You enter these URLs into the phone's Web UI once.
  4. The phone fetches the generated configuration file from that URL and sets up its SIP account automatically.
  5. Whenever the extension number, password, or domain changes, the phone automatically receives the updated settings on its next provisioning cycle.

Step-by-Step Setup​

Panasonic KX-TGP600:

  1. Open the base station's Web UI and log in as admin.
  2. Go to Maintenance > Provisioning Maintenance.
  3. Paste the Standard File URL and Master File URL from the 4phone dashboard.
  4. Save the settings and reboot the base station.
  5. Verify line registration under Status > VoIP Status.

Yealink T3/T4/T5:

  1. Open the phone's Web UI.
  2. Go to Settings > Auto Provision.
  3. Paste the Server URL from the 4phone dashboard.
  4. Save the settings and trigger Auto Provision or reboot the phone.
  5. Confirm that the account is registered under Account.

Grandstream GRP26xx:

  1. Open the phone's Web UI.
  2. Go to Maintenance > Upgrade and Provisioning > Config File.
  3. Select HTTPS in Config Upgrade via and paste the Config Server Path from the dashboard.
  4. Click Save and Apply, wait for the phone to reboot, and check the line status.
Important

You can regenerate the provisioning token at any time. Doing so invalidates the old URL, so you will need to paste the new URL into the phone.

Tip

You can optionally record the device's MAC address in the profile for reference, though primary identification uses the unique token in the provisioning URL.

Where to Find Registration Credentials​

After creating an extension, open its card in the extensions list and click the info button. You will see a ready-to-use panel with all connection parameters:

  1. server;
  2. domain;
  3. username;
  4. password;
  5. SIP ports;
  6. WebSocket URL (if WebRTC is enabled).

Every field can be copied directly from the interface.

  1. Create the extension.
  2. Assign it to an employee.
  3. Enable WebRTC if the employee works in the browser.
  4. Save a custom password or leave the field blank to auto-generate one.
  5. If the employee uses an external device, copy the SIP credentials from the extension card.
  6. Ask the employee to open the browser softphone widget or register their external SIP client.

When to Enable Call Recording​

When call recording is enabled on an extension, 4phone records calls involving that employee.

This is especially useful when:

  1. you perform quality assurance reviews;
  2. you need a record of customer agreements;
  3. your team handles sensitive or disputed inquiries.
Important

Enabling the recording toggle does not make audio files appear mid-call. Recordings become available after the call finishes and post-call processing completes.

When to Enable Voicemail​

If an employee might not always answer in time, voicemail lets callers leave a message. This is particularly helpful for personal DID routes.

How to Verify Your Extension Setup​

Signs of a working extension
  1. the extension is active and visible in the list;
  2. it is assigned to the right employee;
  3. WebRTC is enabled if the employee uses the browser softphone;
  4. the employee can connect via the browser softphone or an external SIP client;
  5. SIP registration parameters are visible and copyable in the extension card;
  6. an inbound or internal test call rings the extension.

Common Causes of Issues​

  1. the extension was created but not assigned to an employee;
  2. WebRTC is disabled;
  3. an employee is trying to connect to an extension assigned to someone else;
  4. the extension is disabled;
  5. the external SIP client has only the shared server address configured without the tenant-specific domain;
  6. the full SIP URI was entered as the username where the client expects only the extension number;
  7. the password was changed, but the browser or SIP client still has old cached credentials.

Next, it is helpful to open How to Use the Softphone.