After completing a successful BCILOGON command, BCI converses with a User Services procedure defined to the product region. The BCILOGON command makes an initial menu selection of U (for the User Services menu).
By using the optional MENU operand of the BCILOGON command, additional data can be passed to the initial procedure to invoke a special procedure for conversing with BCI. This initial procedure uses the &ZPSKIP NCL statement to receive and process this data in the usual manner.
Note: For more information, see the Network Control Language Reference Guide.
As previously mentioned, BCI makes use of the Virtual 3270 Interface. The User Services procedure (and its associated panel) used for the conversation must meet certain basic requirements. The first screen line on the panel should contain three output fields for control information. The second line is an input command line, and the remaining lines are used to return any output data. The supplied procedure ($USERBCI) and panel ($USV3270) conform to these standards and should be used as a model.
BCI defines itself to the Virtual 3270 Interface as a 3270 Model-4 and, while it will only send a single command on the first input line of the panel, it will accept up to 41 data lines in the response (the Model-4 type terminal contains 43 lines of 80 characters each).
After any command has been processed by the procedure, including the BCILOGON command, the first two control fields are reported as the panel name and procedure name respectively. The third field is regarded as a return code, and set as &RETCODE. If this is non-zero, the user is disconnected and documentary messages written to the system output file. The job is canceled with a JCL return code of 12.