TRIO uses Converter internally to marshal and unmarshal calls to an invokable interface. That is, when the TRIO object has been typecast to an invokable interface, it implements each method call by using Converter to marshal the call into an encoding protocol, and to unmarshal any return values after that call is executed. 

Each TRIO descendant uses its own protocol-specific helper object as the value of the Converter property. 

WebNode 

TOPToSoapDomConvert