To open the Device Ports pop-up window click the DevicePorts button (yellow ellipse):
The Device Port window includes all input and output ports as well as EF flags for for all supported Cosmac Elf 2000 HW extensions. All input/output ports can be defined from 1 to 7 depending on what the software expects and what HW you want to emulate. Controls will be disabled for all HW that is not configured. The EF flags can be specified from 1 to 4.
The most common values for all device ports are defined as default.
If EF1, EF2 and EF3 are not used in the defined configuration they will default to '1'. This default value can be changed by selecting '0' for any of these EFs under the 'Unused EF' heading.
Note that no input/output port or EF flag should have the same value if the extension is used at the same time.