CATCH Error

Hi Friends,

I want to catch errors which are not shown in ST22. But I can see errors in sm21 as;

R49 Communication error, CPIC return code 020, SAP return code 223

R5A > Conversation ID: 65932358

R64 > CPI-C function: CMSEND(SAP)

How can I catch this error?

Note : My App. Server is 4.6C

Thanks.