This is something I've copied/revised from socioscope.com.
It emphasises that the role function "works" influenced by the ego functions, so it's different than for those types for whom it's a dominant function (ie the role function of EXFjs is "filtered" - or whatever - through their dominant ).
So, role functions:
(ESTp, ESFp): requires them to be an understanding and thoughtful person
(ENTp, ENFp): forces them to constantly demonstrate to others their penetrative and volitional qualities
(ISFp, ISTp): expects them to be careful and farsighted
(INFp, INTp): insists on the observance of good taste in exterior appearances
(ESFj, ENFj): makes them want so much to be seen as real professionals in their fields
(ISFj, INFj): indicates a constant neeed for learning and being objective
(ESTj, ENTj): makes them certain that everyone expects from them demonstrations of cheerfulness and energy
(ISTj, INTj): forces them to learn the socially-accepted standards of politeness and ethical behavior