DONATELLO -- 2514 L St. NW. 333-1485. Open: for lunch Monday through Friday 11:30 a.m. to 3 p.m.; for dinner Monday through Thursday 3 to 11:30 p.m., Friday 3 p.m. to 12:30 a.m., Saturday 5 p.m. to 12:30 a.m., Sunday 5 to 11:30 p.m. All major credit cards. Reservations suggested. Separate non-smoking section. Prices: lunch appetizers $3.95 to $4.95, entrees $6.95 to $8.95; dinner appetizers $4.50 to $6.25, entrees $10.95 to $16.95. Full dinner with wine or beer, tax and tip about $30 to $40 per person.

ITALIAN RESTAURANTS HAVE REpeatedly captured the limelight these days, and now Donatello is about to take its turn. This downtown Italian restaurant is shortly to assume management of Windows in Rosslyn, which already within the year has been reoriented from New American cooking to a short flirtation with French cuisine.

For Donatello too it will be a new direction. So far, it has been one of those moderately priced little Italian restaurants with lots of fans, each of whom thinks it is his secret. Now, it is not simply expanding -- it is taking on one of the most glamorous dining rooms in the Washington area. Here, then, is a look at the original Donatello, as a hint to what's in store for Rosslyn.

The L Street location has the advantage of a festive open-air covered terrace and an interior that has the warmth of old brick and unpolished wood and the airiness of a two-story dining room with a balcony, making it both intimate and spacious. While it is formal with its white tablecloths and red carnations in silver vases, Donatello is as easygoing as any neighborhood restaurant -- its neighborhood just happens to be Pennsylvania Avenue.

The waiters make the difference. They are a talkative and paternalistic bunch who freely make suggestions, unabashedly explain to you what the people at the next table are eating and willingly offer to make up combinations of pastas for your group. They represent the kitchen as surprisingly reasonable -- half portions of pasta, a different sauce than listed, an alternative combination of ingredients, a special request? No problem.

This heralds unusual cooperation between kitchen and dining room. What's more, the waiters seem to cooperate uncommonly well with one another. It's a nice place.

The cooking has a few heroic moments, but mostly this is simply good, straightforward Italian cooking. It is not so meticulous that the pastas are perfectly al dente or the fish is cooked to that precise moment before it turns a little dry. The sauces are just fine -- maybe a little thick here or thin there, but nothing to make you feel aggrieved. This is not a kitchen that uses all fresh herbs or cooks its own artichoke hearts, nor does it bake its own bread. But everything looks and tastes generous, and while the vegetable garnishes are no more exotic than buttered snow peas and carrots, they are fresh. And a couple of slices of fried polenta are included.

The antipasto list is familiar: fried mozzarella, stuffed mushrooms, clams casino, mussels and two kinds of snails on the hot list; and prosciutto, bresaola, carpaccio, smoked salmon, squid salad and eggplant with peppers and anchovies on the cold list. There are also several soups each day.

I didn't get far among the appetizers -- it is difficult with more than a dozen pastas beckoning. But they all exceeded expectations. Fried squid was the best I have tasted in a long time, which should put a lot of Washington's restaurants to shame. The squid itself bursts with fresh flavor, and the batter is light and filmy yet as crunchy as fresh-roasted nuts. It's large enough to share as an appetizer, but delicious enough to order as a meal. Eggplant with peppers and anchovies, on the other hand, is a small portion and good enough that you might wish the kitchen had been less concerned with decoration and more with satisfaction. I had no such complaints with the pleasant crab-stuffed mushrooms, and spinach soup was generous not only in its portion but also in the richness of the chicken stock. Another promising beginning would be a salad, particularly romaine with gorgonzola, a kind of Italian caesar salad.

The best pasta I tried is not on the menu but one the waiter said is nearly always available: fettuccine with chicken, sausage, mushrooms, peppers and onions in tomato sauce. The tomato sauces here are thin in texture and heavily herbed, which well suits those forthright ingredients. Such a sauce works slightly less well when teamed with seafood in the spaghetti bucaniera; I prefer these shrimp, mussels, scallops and squid with white wine sauce, which is robust with garlic and seafood juices but doesn't swamp the delicate flavors. Seafood ravioli with lobster sauce, a fancier presentation, was creamy and pleasant but not a standout. There are pastas that suggest meals-in-a-dish, such as cannelloni or rigatoni with veal and sausage, and there are lighter ones, such as linguine with pesto or a rich, delicately flavored fettuccine with four cheeses that blends fontina, gorgonzola, parmesan and bel paese into a dreamy conglomeration. The pastas themselves range from very fragile, golden house-made fettuccine to utterly ordinary, factory-made spaghetti.

The main dish list is long and fairly routine -- shrimp with tomato sauce or garlic and olive oil, a few fish fillets, the usual veal scaloppine variations and veal chops, chicken breast combinations, a steak and a lamb dish. One day the specials included sea scallops that were barely cooked and tuna that was barely overcooked. The veal chop has been perfectly pink and juicy, while the veal scaloppine has been mushy and the lamb just gray throughout. Nothing fails, but not much stands out. The food isn't as delightful as the service, but it is every bit as generous.

For dessert, there are a few rich and creamy house-made cakes that taste pretty much like everybody else's. Creme caramel is routine, white chocolate mousse is a little sweeter than most, cannoli are a little creamier than most. But since the appetizers are the stars and most portions are large, none of this may be relevant.

In its present form Donatello is no threat to the big-name Italian kitchens. It is an inviting restaurant that occasionally rises to such heights as the fried squid but generally serves food that wouldn't draw much notice except that it leaves its customers feeling well treated. In its expansion to Rosslyn it will face the challenge of a more imposing space and a location that is a destination rather than a neighborhood. And there's the matter of doubling the supply of waiters -- Washington is even hungrier for good waiters than for great fried squid.