CLSDST →      RPL:    ACB field → ACB
                      Note: ARG and NIB are mutually exclusive.
                      ARG field = CID of session terminated
                      NIB field → NIB:
                           Note: NAME and CID
                           are mutually exclusive.
                           NAME field = symbolic name of LU
                                      whose session
                                      is terminated
                           NETID field = symbolic network identifier of LU
                      Note: NETID and MODE
                      are mutually exclusive.
                           CID field = CID of session terminated
                           USERFLD field =correlator returned
                                                in NSEXIT exit routine
                           LOGMODE field = logon mode name
                           LISTEND field = YES
                      Note: MTSAREA and BNDAREA
                      are mutually exclusive.
                           MTSAREA field = 0|MTS area address
                           BNDAREA field → 0|BIND area
                      Note: ECB and EXIT are mutually exclusive.
                      If ECB is used, only one is allowed.
                      ECB field → external ECB
                      ECB field = internal ECB
                      EXIT field →  RPL exit routine
                      BRANCH field = YES|NO
                      AAREA field  → name of target PLU
                      AREA field  = user data for Initiate
                      RECLEN field  → length of user data
                      OPTCD field = (PASS|RELEASE|TERMQ,
                                      SYN|ASY,
                                      NSENSE|SENSE,
                                      MTS|NMTS)
                      PARMS field =(THRDPTY=NOTIFY|NONOTIFY)
                      PARMS = (SONCODE = code)
                      SSENSMO field = CPM|STATE|FI|RR|0
                      SSENSMO field = system-sense modifier value (or 0)
                      USENSEO field = user-sense value (or 0)
 
     Registers 0 and 15 = return codes
 
     RPL:          RTNCD field = recovery action return code
                   FDB2 field = specific error return code
                   REQ field = request code (31)
                   SSENSEI field = CPM|STATE|FI|RR|PATH|0
                   SSEMSMI field = system-sense modifier value (or 0)
                   USENSEI field = user-sense value (or 0)