C

class
See message class.
connector
A software service that allows users at one Microsoft Exchange Server site to connect to users at other Microsoft Exchange Server sites using specific protocols such as X.400, SMTP, and Microsoft Mail. Microsoft Exchange Server includes an Internet connector, a site connector for linking two Microsoft Exchange Server sites, and a RAS connector. A connector can perform all the functions of a gateway. See also backboning (backbone).
conversion
A program that translates a message from one messaging system format to another.
conversion engine
A set of functions that convert messages between multiple messaging systems.
custom recipient
An address book entry representing a recipient from another messaging system. A client application user can create a custom recipient with a template supplied by the address book provider.