You can use your hands-free device with the iPhone via the Bluetooth connection.

In order for your car display to show the names of your Swyx Mobile contacts when calls are made from the Swyx Mobile environment, you must store them in the local phonebook, with both internal and external phone numbers. Contacts in the Swyx Mobile app are not available here. If you do not do this, only the extension of the Swyx Mobile contact (e.g. 437) is displayed. Then the local contacts must be synchronized with your car. In most cases, this happens automatically.