Anyone have or seen (assembler) code to implement a z/os vtam 3270 program slu to programmatically logon to e.g. TSO? I successfully issue OPEN ACB, SETLOGON, REQSESS, OPNSEC, and RECEIVE macros to get an initial 3270 datastream logon screen image in storage, but any attempt to then provide a userid via a SEND macro and accompanying datastream is simply ignored. Very little such stuff (understandably) on the web. Thanks.