What are trusted systems?
Trusted systems are systems with a relationship of trust between them. For example, if you have set up a trusted relationship between system A and system B, so that system A trusts system B, a user that has logged onto system A can start a transaction in system B without entering a password but using the user ID from system A. (This is important since a user ID and password in an RFC destination means that all connections result in the same user ID connecting.