MAPI Address Type constants identifies the type of
messaging system MAPI uses to handle a message. The messaging system then
knows how to format the message appropriate to the recipient. The
following are valid constants:
Mapi_Fax
(1) – Facsimile.
Mapi_Mhs
(2) – Novell Message Handling System.
Mapi_Profs
(3) – Professional Office System.
Mapi_Smtp
(4) – Simple Mail Transfer Protocol (Internet Request for Comments (RFC) 822).