The XATMI interface provides the following communication paradigms:

• Request/response service paradigm
  Communication based on this paradigm consists of sending one request to a service function and receiving one response. Like OpenTP1 remote procedure calls, communication is used to request services and receive results.
  
• Conversational service paradigm
  Communication based on this paradigm consists of activating the service function as the destination party and exchanging data to/from the service function via the connection established when the service function was activated.
  The conversational service paradigm is available only when TCP/IP is used as the communication protocol. If OSI TP is used as the communication protocol, the conversational service paradigm is not available.
  

To request a service, use a function whose argument specifies a name (service name) that identifies a service function in the server UAP.

When XATMI-interfaced communication is in use, structures in C or records in COBOL can be transmitted and received. This means that a chunk of data of some size can be sent with a single service request. Such a chunk of data is referred to as a typed buffer in C or a typed record in COBOL. For typed data used in communication, see 5.1.6 Communication data types.