|  | 1 | 
            
              | Interchange is a test |  
              | Indicates that the interchange is a test. |  | 
        
          |  | 2 | 
            
              | Syntax only test |  
              | Test only syntax of structure. |  | 
        
          |  | 3 | 
            
              | Echo request |  
              | To be returned without change, except for this data element to have the value 4. |  | 
        
          |  | 4 | 
            
              | Echo response |  
              | Returned without change except for this data element changing from 3 to 4. |  | 
        
          |  | 5 | 
            
              | Interchange is a service provider test |  
              | Indicates that this interchange is a test with a service provider. |  |