What is the ANSI-92 equivalent of the following old Informix SQL query?

```
select * 
from categories c,
  orders o, 
  outer (employees e, person p) 
where c.categoryid = o.categoryid
  and p.personid = e.id
  and o.employeeid = e.id
  and o.orderid = 7742
  and e.term_date is NULL

```

I cannot seem to figure out exactly what the "outer (table1, table2)" syntax means.