Special Linkage for DB2 Stored Procedure

I try to learn COBOL  a little bit more deeply with VISUAL COBOL,  But I feel hard to understand someone's code like this:

******************************************************

       identification division.
       program-id. gip2trbl.

       environment division.
       configuration section.

       data division.
       working-storage section.
       01 TRBLINP-TYPE          PIC  X(01).  
       01 TRBLINP-SEARCH-DATA   PIC  X(40).

       
       LINKAGE SECTION.                                 
       01 TRBLINP.                                       
           05 TRBLINP-IO-LEN      PIC S9(04) COMP-5.   
           05 TRBLINP-IO-TEXT     PIC X(41).       
       01 OUTDATA PIC X(41).

       PROCEDURE DIVISION USING  TRBLINP, OUTDATA  .
      

        UNSTRING  TRBLINP-IO-TEXT (1:TRBLINP-IO-LEN)
       DELIMITED BY '><'                        
       INTO  TRBLINP-TYPE ,
       TRBLINP-SEARCH-DATA .       
                       
       
        move  TRBLINP-IO-TEXT  to  OUTDATA.    
   
           goback.
           
       end program gip2trbl.

**************************************************************

Then I created DB2 stored procedure on DB2 V10.5

I passed "1><611016007800011"  into stored procedure. 

I expected  TRBLINP-IO-LEN having the real length of the string which I passed  and TRBLINP-IO-TEXT has original string value.

I use out parameter to verify TRBLINP-IO-TEXT.  but I only get "<611016007800011",   not "1><611016007800011"

Could someone explain to me how to make it working correctly ?

Really appreciated.