eth·ic (thk)n.
a.A set of principles of right conduct.
b.A theory or a system of moral values:

ethics (used with a sing. verb) The study of the general nature of morals and of the specific moral choices to be made by a person; moral philosophy.

ethics (used with a sing. or pl. verb) The rules or standards governing the conduct of a person or the members of a profession.

Ethics is the blue print by which we live our life…or,  put another way, it is a set of laws based in our faith in a  creator and his unmistakeable Goodness.  All Ethics comes down to one point, the difference between 'good' and 'evil'. Students can improve themselves physically, and mentally by training. Ethic is the tool by which we train our spirit. The final goal is to achieve harmony with nature and oneself. Balance is gained by controlling both evil and good forces (Yin vs. Yang): A true student knows how to behave in all situations. Ethics is a way of life.

ETHICS AND DOCTORINE
Etiquette
Because of the military background, there is a general code. These codes are reflected in the so-called 'Commandments of modern Tae kwon do' and is strongly influenced by Buddhism and the Hwa Rang Do code of honor.
Hwa Rang Do code of honor:
1.Serve your lord with loyalty
2.Serve your parents with filial piety
3.Trust your friends
4.Never retreat from a battle
5.When taking life, be selective

The commandments of Taekwondo are used as a guide for the moral development of students and the art.  No student who does not fully understand these tenets can ever hope to master the true essence of Tae kwon do.

Commandments of modern Tae kwon do:
1.Loyalty to your country
2.Respect your parents
3.Faithfulness to your spouse
4.Respect your brothers and sisters
5.Loyalty to your friends
6.Respect your elders
7.Respect your teacher
8.Never take life unjustly
9.Indomitable spirit
10.    Loyalty to your school
11.    Finish what you begin

Etiquette depends on a lot of things. Of importance are the attitude of the teacher, the country you live in and of course, what you think of it. I personally like to add some things I think are of importance too.
·Show respect
·Respect your teacher and the other students (not just the higher ranked!).
·Respect the dojang
·Respect your opponent.
·Enter the dojang properly
·Behave correctly.

There are a few general rules on how to behave in the dojang .
·Always wear a clean and ironed Dobok(uniform).
·Don't wear sharp things (if you do not have a Dobok, do not wear pants with zippers etc.)
·Clean hands, feet, short nails.
·No jewelry allowed
·Don't drink, smoke or eat in the dojang (no chewing gum!)
·Be on time.
·When entering and leaving the dojang, make a proper bow
·Don't talk, unless it is urgent