BiDirectional interface

It all depends on what type/format of data you're trying to exchange and how you want to exchange it.  Is it HL7,  SWIFT, custom format...? Will it be via a file, email, TCP/IP, FTP...?  There are adapters available in Health Connect to use in services and operations that will handle a wide variety of types and protocols.  Have you taken a look at the online materials in the InterSystems Learning Portal?  There's a resource guide Learn Ensemble for Developers and System Integrators (Ensemble was the precursor to Health Connect) that may be helpful when first starting out.  It has a lot of information about how to design and build integrations.

If you provide a little more about what you're trying to do, it'll help in being able to provide more specific guidance.