2.1.1033 Part 1 Section, RTD

a.   The standard does not describe restrictions on progID.

In Office, if progID does not reference an application that is registered and that implements IRTDServer, then #N/A is returned.

b.   The standard does not describe how the application communicates with Excel.

In Office, the application must implement the IRTDServer interface.

c.   The standard does not specify that argument-list may be left blank.

In Office, argument-list is required, but may be left blank.

d.   The standard uses the following syntax: RTD(progID, [rtd-server], argument-list).

Office uses the following syntax: RTD(progID, rtd-server, argument-list).

e.   In the standard, argument-list does not specify the maximum number of arguments.

In Office, argument-list may contain at most 253 arguments.

f.   The standard describes the rtd-server argument as a string that is specific to the application with which RTD is communicating.

In Office, the rtd-server argument is used to perform a DCOM call to a remote RTD server. It is not specific to the RTD server.  If there is no server and the application is run locally, the argument is left blank.