You can configure pickup option if your PBX supports it.
Call pickup configuration
Please note that commands herein may differ from commands adopted in your PBX. Please contact your PBX vendor for correct DTMF commands.
1. Open your SIP account settings: Settings - SIP Accounts - Your SIP account.
2. Set your call pickup command (depends on your PBX settings) in the Call pickup (DTMF) field:
Use %EXT% placeholder to replace it with contact's extension number when using call pickup.
3. Click Save.
Call pickup use
1. In the Contacts window Click the Call button of a contact with extension number:
2. You will see a Call pickup option in the dropdown with the command you configured. Should you use %EXT% placeholder, you will see a Call pickup option in the dropdown for each extension number in the contact:
3. Select Call pickup option from the dropdown to dial the command and pick the call up.