Thanks for your question. As you've noted, there are four key principles in ethical and intercultural communication.
In order to communicate with people from different ethical backgrounds, it is necessary to stay open minded and understand that we are not all the same or built the same way. Here are the four main principles.
1. Expect differences
Ethics and culture largely pertain to relativism and moral relativism. Therefore, we are all hugely different, particularly in our belief systems. That which is deemed 'good' and 'bad' is generally conditioned beliefs/behaviours in different cultures. In order to establish good intercultural communication, it is necessary to keep an open mind when it comes to these differences and appreciate that people may think entirely differently to the way you do, and that does not make them wrong or right, just different.
2. Use universal language
The best way to converge with people of a different culture is to find the common ground. We all know of certain ethical principles which are shared around the globe. This is generally a good starting point for finding a common ground in an unfamiliar territory.
3. Learn from them
Discover boundaries in their cultures. Learn the differences and commonalities between you. Since foreign cultures are likely to have an alien perspective of what is deemed 'good', it is important to identify just what that is. When you can do so, and understand their perspective, it opens the door to far better communication.
4. Show empathy and respect through action
Once you have learnt, understood and appreciated another culture, the most important part is learning to respect it and applying this to how you behave. Once you have understood what is and what isn't deemed as 'good' or 'correct', good intercultural communication involves demonstrating that you can abide by these ethical standards as a means of respecting that culture.
I hope this answers your question.