Jake has a post of local (to Bend) telephone prefixes. Good resource. And he says, "When I lived in Bend growing up, I knew if the phone number didn’t start with 38-something (382, 385, 388, 389, and then 383 came along later) or 593, it was a long-distance call." I remember, too, when it was just 382, 388 and 389; people would regularly write phone numbers with only the third digit of the prefix (e.g., 9-0123).
Of course, only having to dial four digits is a little before my time; even though the "38" part was assumed, you still had to dial the full seven digits. And yes, calling Redmond (which was only 548, and later, 923), was long distance.