Data Interfaces

General Flow
System 1 System 2
© SAP AG
Initialize Initialize connection
connection
Set Set up up connection
connection
Send Send data data
Receive Receive data data
Send Send data
data
Close Close connection
connection
Side Side info
info
table table
(Client)
Program 1 (Server)
Program 2
Accept Accept connection
connection
Receive Receive data data
Send Send data
data
Receive Receive data data
Close Close connection
connection
With program-to-program communication, the general flow is the same regardless of the programming
language used. The following rules apply:
- With half duplex communication, only one program is authorized to send data at any one time. When one
program is in send mode, the other is in receive mode.
- The program setting up the communication always has the right to send data first.
- The other (started) program is in receive mode first.
- Switching the direction of the communication is achieved by setting off CMRCV in send mode. Then, the
partner program can send data.
- Mutiple communication switching is possible.
One program sets up the connection ( = client); a partner program accepts the connection ( = Server).
In the communication initiator system, a side information table must exist. This table is needed for the
connection initialization.