You can use an ISDN or Analogue line for incoming calls.

During start-up, the phone will automatically check what type of line is connected. When no line is found, ISDN will be the default value.

To switch to an analogue line, you need to connect the line and restart the phone, the device will switch to the analogue line if found.

When using the analogue line, you need to use the special cable that is in the packaging.

The analogue line is connected to the PIN 1 and 8 of the RJ45 jack, see the picture below.