IBM SC33-1683-02 - Manual (Page 243)

For START commands issued in this system by transaction routing
to a task, the netname of the last system from which the task was
routed.
For other START command situations and for transient data trigger
level events, the field pointed to contains blanks.
UEPALSYI
Address of 4 bytes containing, if UEPALNTI contains a netname,
the corresponding sysid.
If UEPALNTI does not contain a netname, the field pointed to is
blank.
UEPALNTO
Address of 8 bytes containing the contents of UEPALNTI.
If it sets a return code of ‘UERCNETN’, your exit program must
place in this field the netname of the system to which the ATI
request should be sent.
UEPALSYO
Address of 4 bytes containing the contents of UEPALSYI.
If it sets a return code of ‘UERCSYSI’, your exit program must
place in this field the sysid of the system to which the ATI
request should be sent.
UEPALNNI
Address of a 4-byte input field containing the netname of the
terminal on which the transaction is to run, if this is known to CICS.
If CICS does not know the netname, the addressed field contains
blanks.
UEPALNNO
Address of a 4-byte input/output field containing, on invocation, the
contents of UEPALNNI. Your exit program can use this field to
supply the netname of the terminal on which the transaction is to
run. It is important that your exit program supply a terminal
netname if the TOR to which it directs the ATI request is a member
of a VTAM generic resource.
Return codes
UERCTEUN
Terminal unknown, reject request.
UERCNETN
Terminal known, netname returned in UEPALNTO.
UERCSYSI
Terminal known, sysid returned in UEPALSYO.
XPI calls
You can use:
INQ_APPLICATION_DATA
INQUIRE_SYSTEM.
No other XPI calls should be used.
terminal not known condition exits
Chapter 1. Global user exit programs 211