The comparison semantics for values of a LDAPSyntaxes are not part of the LDAPSyntaxes definition but are instead provided through separately defined Matching Rule.
Matching Rules specify an argument, an Assertion Value, which also has a defined LDAPSyntaxes.
Microsoft Active Directory has several LDAPSyntaxes that are NOT defined within RFC 2252 or RFC 4520[1]. We have accumulated them as best we can in Microsoft Active Directory Syntax
LDAPSyntaxes - per RFC 4520 are defined within an IANA Registry Lightweight Directory Access Protocol (LDAP) Parameters located at: LDAP Syntaxes