struct dlccb        {
     char sdecb      ;       /* code request               */
     short type      ;       /* type request               */
     int count       ;       /* count use                  */
     char area[4]    ;       /* addr of data               */
     short len       ;       /* length of data             */
     char flag0      ;       /* flag 0                     */
     char flag1      ;       /* flag 1                     */
     char rtn[4]     ;       /* routine addr               */
     char typei      ;       /* index dlc-routine          */
     char typ        ;       /* type VT                    */
                    };
#define DLCVT 0x01           /* flag VT                    */
#define DLCLAN 0x02          /* flag LAN                   */