If you’ve ever had a missionary ring your doorbell, you might be surprised to learn that some Mormons are now turning that skill into a second career during these tough economic times:

Six days a week, in fair weather and foul, two-dozen door-to-door salesmen, all of whom live clustered together in an apartment complex in this suburb west of Chicago, pile into S.U.V.’s and cars and head into the big city, bent on sales of home security systems.

And on Sunday, their one day off, they drive together to the nearest house of worship of the Church of Jesus Christ of Latter-day Saints.

The salesmen are mostly former Mormon missionaries from Utah who cut their teeth — and learned their people-skill chops — cold-calling for their faith. In Chicago and in its suburbs where their employer, Pinnacle Security of Orem, Utah, has shipped them for the summer sales season, they are doing much the same thing, but as a job.

“It’s missionary work turned into a business,” said Cameron Treu, 30, who served his mission in Chile and was recruited into D2D (that is door-to-door in sales lingo) by another former missionary.

Managers at Pinnacle Security, founded in 2001 by a student at Brigham Young University, the Mormon Church-owned school, say missionaries simply have the right stuff. Many speak foreign languages learned in the mission field. All have thick skins from dealing with the negative responses that a missionary armed with a Book of Mormon and a smile can receive.

Mormon men are expected to serve a two-year mission in their early 20s, and about two-thirds of Pinnacle Security’s 1,800 sales representatives this summer have been through the experience. Former missionaries work for other direct-sales companies, too, though Pinnacle seems to be in a class by itself: It has deployed them in 75 cities nationwide.

“They’re used to knocking on doors, and they’re used to rejection,” said Scott Warner, Pinnacle’s manager of the Chicago sales team.

Mr. Warner said interest in the security products was up this year — a recession indicator, he said — as people reacted to fear (if not always a statistical reality) of rising crime. But the number of potential customers who cannot pass credit checks is up, too, with more homeowners unable to afford the $40 or so a month that Pinnacle charges to monitor a system. The company also charges a $99 installation fee, but nothing for the alarm equipment itself.

As millions of traditional jobs dried up last year, at least 100,000 Americans joined the ranks of what is called, in the trade, direct sales. With items like cosmetics and skin care (Mary Kay, Avon) and housewares (Cutco knives, Fuller Brush), more than 15.1 million people are now selling something, or trying to, somewhere far beyond the mall.

And retention is up in a profession with a notoriously high burn-out rate, industry experts say. (Fifty to 100 door-knocks a day, with one or two completed sales, is an average grind.) At Pinnacle Security’s Oak Brook office, for example, only about 15 percent of the reps had given up and gone home, or not worked out to expectations, after the first month of the sales season, which began in early May — about half the normal attrition rate.

PHOTO: by Carlos Javier Ortiz for The New York Times