To maximize the number of different client languages that use the OpenROAD Server, all server facilities are accessed using COM automation-compatible interfaces. This means that parameters passed to the remote 4GL procedures must be expressed within the set of data types that COM automation supports.

This common denominator provides a rich collection of types, but does not include all the object types (such as system classes) that an OpenROAD procedure might accept as parameters in a purely OpenROAD context. When an OpenROAD client makes a remote call to an OpenROAD Server procedure, the parameter types that can be passed are the set of types that can be converted to and from COM automation types.

The primary purpose of the OpenROAD Server is to allow many different client languages to share the same OpenROAD 4GL business logic. Remote 4GL procedure calls are limited to the common denominator of automation parameter types, and therefore cannot duplicate all the functionality of purely local OpenROAD 4GL procedure calls.