From the outside, the dusty white ice cream truck plastered with makeshift signs -- such as "We have shopping bags" -- looks almost sinister, parked in the middle of the Kenilworth Courts housing project with a long line of children at its side window.

Policemen new to the beat have been known to stare curiously. This neighborhood fears street vendors who double as drug pushers. But the mothers of Kenilworth, a poverty-ridden, self-contained neighborhood sandwiched between Kenilworth Avenue and the Aquatic Gardens in far Northeast Washington, know better.

This truck belongs to Al Carthens, who is no ordinary street vendor. He is the food man, the main merchant in a corner grocery store on wheels, a poor man's answer to co-operative economics, and for many in Kenilworth Courts, an indispensble lifeline.

Carthens does a modified cash-only business in one of the roughest neighborhoods in Washington, but in 10 years, has never been robbed, he say.

Like a businessman in the city's thriving illegal numbers game, he readily extends credit to some of the poorest of Washington's poor. It is closely tied to the first and 15th days of the month -- the day welfare checks are mailed. He charges no interest, no carrying charges. A familiar face is as good as a signature on the dotted line.

He is a major source of fresh vegetables in an area so neglected that back yard gardens are discouraged because they nourish more rats than people.

"A lot of people depend on him to provide food, especially when they don't have any money," says Kimi Gray, president of the Kenilworth Courts Residents Council. "There are a few people out here who get pretty desperate around the end of the month -- I mean downright hungry. Al will pack a bag and tell them to see him when they can."

"Good man to have in the neighborhood," said James Gordon, an elderly resident who had just bought a small can of Franco-American spaghetti and a package of crackers for lunch. "It's convenient, but mainly he's a nice guy. If I don't have enough money, he knows I will bring it back. The [store owners around the corner] don't want to hear it."

Inside Carthens' truck, makeshift shelves bulge with a day's supply of food, household items and staples -- stockings and Pampers, fresh bread, eggs and milk. Canned Vienna sausages with a package of crackers "sell like crazy," he says.And there is toothpaste, toilet tissue, bars of soap and Clorax; Baby Ruth, Three Musketeers, penny candy, and, by the way, ice cream. A list of his current creditors is scrawled on a piece of paper taped to the wall.

Carthens, 42, is a native son of the city's housing projects. "The reason I survive is because I understand these people," said Carthens, a small, eagle-eyed man, as he double-checked the last sale date on packages of pastries before giving them to clump of children standing around the truck. "They are just like me -- poor, but trying to make ends meet.

"Now, I do make a living off of them. So I feel obligated to do what I can to help them make ends meet." The living he makes, his mother Daisy Carthens estimates, is about $400 a week profit, much of which is plowed back into the business.

Carthens runs a business born of necessity and the conditions of life in this poor black section of the nation's capital. Except for a 7-Eleven store on the other side of the busy highway and a delicatessan a block away from the edge of the sprawling housing complex, there is no other food store within what many consider a reasonable walking distance.

Carthens was born in North Carolina while his mother was there on a visit. He grew up in Parkside, a Northeast housing project that the city tore down in 1968.

The family then moved to Kenilworth. His father, Ted, drove a cab for 17 years and then worked as a nurse's aide at the Glenn Dale Hospital in Maryland.

Al Carthens, the second oldest of seven children, had worked as a shipping clerk for a potato chip company until the clerks went on strike. When his father became ill and the household income ceased, Carthens suggested that the family get an ice cream truck.

Described by his mother as "naturally easy-going," Carthens takes his time stocking the shelves and always manages to spend a few minutes bantering with his customers. Most of them he has known for a decade.

Although in his 40s, Carthens looks a lot younger. He wears casual work shirts, blue jeans and a fishing hat. The van stays open until he feels that he has done his "good deed" for the day. After that, he may drive down to Waldorf and go fishing.

"We all deal together out here -- everybody pulls together and tries to help one another," Carthens said. "That's the only way you can make it in a place like this. It's all about coping and being able to survive."

Skeptics may see hidden motives. But a reporter who spent two days with him found Carthens to be pretty much as he claims.

On holidays such as Easter, Christmas and Thanksgiving, Carthens buys crates of beef and hot dogs and throws a free barbeque for the residents. When the Kenilworth Courts baseball team needed money for hats and shirts, Al said, he helped pay the bill.

"People always wonder what am I getting out of it. You know how they are -- getting jealous because they think I'm making too much money. I try to point out that as a businessman you have to make a gain if you're going to maintain."

At first, he hustled heartily to keep his operation afloat. There was competition from other vendors, so he had to come up with something nobody else could do.

Carthens began selling bus tokens -- not a competely above-board operation, but a service desperately craved by this community of bus riders. (He has since stopped selling them.) Within months, the Kenilworth residents council, in appreciation of Al Carthens, voted to ban all vendors except him from the neighborhood. That was mostly a symbolic gesture, since few others were operating there, anyway.

"I don't know what this community would do without him -- he's such a soft heart," said Daisy Carthens, head sales manager for the Daisy Vendor Service.

Carthens' day begins at 6 a.m. with rounds to local wholesale outlets. Using a tried-and-true marketing technique -- people tell him what they want and he goes out and buys it -- Carthens fills the truck of his aging Lincoln Continental and arrives back at his truck at 8 a.m. It's opening time and a line has already formed.

"Gimme some soap," a sleepy-eyed child commands, struggling to hold onto a fistful of coins.

Next, a pregnant teen-ager ambles up to the truck window. "I see you're out there again," Mrs. Carthens says, as she reaches for a jar of apple sauce.

"I swear," the teen-ager exclaims.

Sheila Pollard, 22, brings a petition to the window. She lives across the street. D.C. school officials are trying to close the Washington Street Academy, Pollard reports. "They are trying to close all adult schools. Can you sign so I can stay?"

Mother Carthens, as many call her, takes the paper, pen in hand. "Sounds like 'Reaganomics.' We got to start fighting for everything now, my dear."

As the day goes on, a view emerges from the van window of a housing project that belies its image as a haven for those who do not care.

Push-type lawn mowers clatter about. Furniture is painted and cars worked on in the streets. Around noon, Al pulls out a crate of half smokes and some hot-dog buns and throws an extra case of colas in the cooler. He will be cleaned out by the end of the day.

The Carthens van is a family operation. His mother and his aunt, Pearl Brandon, monitor sales. Along the wall of the van are makeshift credit charts with a list of names and tabulations scratched out with magic markers. One list shows that PeeWee, Ricky, Husky and Lillian are paid up. Peanut, however, still owes $23.50, according to the records.

Polaroid snapshots of family members adorn the truck. Frayed at the edges is a fading one dollar bill -- the first buck earned. There is a battery-operated television for the daytime soap operas and a bowl containing the remnants of a batch of freshly cooked collard greens.

Al Carthens does not subscribe to being a universally liked man. Some complain that his prices are too high, even though his low overhead allows him to sell more cheaply than chain stores and other neighborhood grocers. His selection, of course, is more narrow.

And he risists the urging of some Kenilworth Courts residents that he move his store into a vacant basement apartment and expand his stock. That would be less secure than his truck, he says, and cramp his open-air style.

His business puts him at peace with himself and his neighbors, he says.

"I stick my neck out by giving credit, and that makes me feel good. When I see a a kid that I have watched grow up from knee high to as big as me and I know I had something to do with it, that makes me feel good inside. That's what this is all about.

"I know I'm not the greatest or somebody big time, but I just can't stand to see people suffer. I know there aren't many people around who will just loan you money, and I have been burned. But I don't stay mad long. When I see the look on somebody's face who has managed to get back on their feet and can pay up, that smooths things out for me."