ASN.1 Structured Data Types

SET(17)

a fixed, unordered set of distinct types, some possibly optional

SET OF(17)

an unordered list of zero or more of the same type

SEQUENCE(16), SEQUENCE OF(16)

a fixed, ordered list of distinct or same types.

CHOICE(11)

like SET, except more general.

ANY

like CHOICE, except containing a list of anything that can be defined in ASN.1

messageBodyPart ::= CHOICE {
    [0] IMPLICIT asciiText, -- note TAG*
    [1] IMPLICIT telex
    ...etc... }