Atmosphere: Plain; come as you are.

Hours: 9 a.m. to 11 p.m. Monday through Saturday; 2 p.m. to 9 p.m. Sunday. Price Range: Sandwiches, $1.35 to $2.20; Dinners, $3.50 to $8.95.

Reservations: Not taken.

Credit Cards: Visa

Special Facilities: Parking in lot in rear of restaurant; not accessible to handicapped; boosters and high chairs available; cocktail menu.

Like that institution, the diner, the Calvert House Inn is a little bit of Americana. It's reminiscent of the roadhouse restaurants that used to exist at rural crossroads before the dining out craze drove restaurateurs to hang swinging ferns from every available ceiling nook, and families to drive the Beltway in search of culinary experience.

In the bad old days -- say around 1949 -- eating out in the suburbs meant:

a hamburger at a drive-in;

chow mein from the Chinese carryout; or

stopping at the sight of a neon sign that read "Steak and Cocktails."

This last was at least half local pub, where one could sit down to simple food that might be well prepared and satisfy one's desire to eat chicken out of a basket, as opposed, I suppose, to chicken on a plate.

So it is at the Calvert House Inn. A long and unfancy bar dominates the rear of the place. Up front, booths flank the walls with a few tables in the center.Named for its proximity to the Calvert Mansion, where once lived the Lords Baltimore, it pretends to be a bit colonial in atmosphere, with Williamsburg chandeliers and hurricane lamps over the candlesticks. The light is dim, which means that the baby can chuck melba toast on the floor all night and no one will notice. On the other hand, it's hard to read the menu.

The offerings here are pretty straightforward: Steaks, seafood, chops, and the ubiquitous chicken. Prices are reasonable, with most selections about $5.95.

However, the absence of a children's menu seems strange. A few sandwiches are available, but most, like crab cake, would not please a child. Unless he wants a hamburger, a child must order a full-sized and full-priced dinner. It would be simple enough to put fewer pieces of chicken in the basket and knock a dollar or two off the price.

There is a small but pleasant salad bar based on a fresh bowl of iceberg lettuce and most of the usual toppings. Nine-year-old Amy declared it to be her kind of salad bar -- in other words, there were cucumbers, bacon bits, croutons and a good blue cheese dressing.

Dinner itself was another matter. Our plates of seafood and chicken were generously heaped with more food than we could eat, but it was all overcooked, undercooked or tasteless. Vegetables were of the canned and warmed-over variety. Our "baked" potatoes had been steamed in aluminum foil, but not nearly enough. They were too hard to be enjoyable.

Broiled mackerel, a Monday night special, sounded good, and our waitress recommended it. But the cook must have put it under the broiler and gone out to lunch -- it was dry and flavorless. Ditto the fried seafood platter: Shrimp were tough and small oysters had been cooked to a shrivel.

A large crab cake was more filler than shredded crab, and had no discernible seasoning. Only the scallops were palatable.

The girls ate some of their fried chicken, but they pronounced it tough.

The Calvert House does have a local clientele who seem to like it. we nibbled our way through a couple baskets of Kaiser rolls and wondered if some of the regulars seated around us knew something we didn't. One couple was doing the steak and cocktail thing, and the steaks looked rare and appetizing. At $5.95 to $8.95, they are reasonably priced. Another couple sipped wine and quietly played backgammon while they ate. We tried a few games of tic tac toe, but it didn't seem to help.

When our waitress offered us dessert, we decided it was time to cut our losses and headed for the local ice creamery for cones to eat on the way home. The evening cost us $40.71, tax and tip included.

If you feel like a steak and cocktail and some late '40's deja vu, you might try the Calvert House Inn, but you'll probably get better value for your money by going farther down the road and driving in for a hamburger.