Stephen Canton knows that sales is a numbers game. For every 10 doors you knock on or people you pitch, you are going to score a couple of times.

Hustle. Put yourself in front of the potential client. Make your pitch. Close the deal.

It’s a lot like reporting. I learned early on in this business that success is often a function of making enough phone calls, knocking on enough doors, talking to enough people. You put up the numbers, and sooner or later you will get the information.

It’s not rocket science.

Persistence has made Canton (not me) a lot of money. He won’t say how much, but he’s worth tens of millions, at least. He earns a six-figure income. Drives a Tesla, a high-end electric car. (“If you’re in technology, you should drive technology.”) He owns three homes. All thanks to a list of hits in the telecommunications business going back three decades.

All built on the ability to sell.

His latest venture is McLean, Va.-based iCore Networks, which he launched in 2003 with a $7 million personal investment. It sells Internet phone service to businesses, competing with traditional phone companies such as Verizon and AT&T.

ICore expects to earn $6 million this year on sales of $59 million. It employs 150 people and is planning to expand that to 200 soon.

Canton owns 51 percent and is talking with several Silicon Valley private-equity firms about a large investment, perhaps $50 million to $100 million, to enable iCore to expand nationwide and eventually go public.

Canton was moving fast last week, phoning me from a car in San Francisco or an airport somewhere as he visited potential iCore investors —in person, of course, just as he does when selling.

“You have to make a point of going in person . . . stopping by. You get their attention by walking through the door. Out of every 10 cold calls, you see two or three guys.”

He parses the science of selling into five parts: attention, interest, desire, conviction and close.

From there, it’s all about convincing the person that your product can save them money, improve their productivity and increase profits.

“I made big money doing that,” said Canton, who started selling dictation machines out of his Volkswagen Beetle in Prince George’s County in the 1980s. He banged on office doors, his dictation equipment buried in the suitcase that he was carrying. The only money he made, which was about $12,000 a year, came from sales commissions.

I asked how he deals with the constant rejection that salespeople must endure.

“Fear of failure drives you,” he said. “You eat what you kill. You don’t kill, you don’t eat.”

There’s more to it than that. His tolerance for the conflict inherent in the free-market system was steeled over the years. At 13, he witnessed his father, a general surgeon in Washington, suffer a stroke and become paralyzed. His father, and the family’s resources, slowly diminished over the course of a decade, leaving his mother to care for his eight brothers and sisters.

“I had to pull Dad out of bed and get him dressed,” he said.

Then there was Canton’s bout with an advanced stage of testicular cancer at 28. Thirty years later, he has three daughters, and works and plays with exuberance.

“You get ups and downs and play through them. You get knocked down, and you get back up.”

He was a terrible student in school, getting kicked out of Gonzaga and then attending Western High (now Duke Ellington School of the Arts). He went to Regis University in Denver for a year, getting some financial help from an older brother who was a physician. Then he quit and came back to Washington in 1979, when he was in his early 20s.

Another brother helped him get a $2.50-an-hour job in the stockroom of Lanier, an office-products company in Arlington County. He worked his way out of the stockroom and into a sales job, which is how he came to be selling dictation machines — and the high-margin maintenance contracts that went with them — to lawyers and businesses in Prince George’s.

He soon realized a commission-based $12,000 income selling dictation equipment wasn’t going to get him where he wanted to be. He contacted a recruiter, puffed up his résumé and took a salaried job in New York for upstart TDX Systems. The year was about 1981, and TDX was then competing against big phone companies for long-distance service for businesses.

He was commanding a staff of six salespeople from a small office on Park Avenue. His base pay was $36,000 a year.

Instead of hiring seasoned industry salespeople, Canton hired young men and women straight out of college whom he could teach his method of selling.

“I wanted them because they had no pre­conceived notions. They were a blank canvas.”

Canton was in the field every day with the troops, going office to office, sometimes employing a Southern accent to put potential customers at ease.

“They would say, ‘Where are you from, Alabama?’ I would say, ‘Sure, just came to see you.’ And they would say, ‘Get in here. How did you find us?’ ”

Soon they were outselling nearly every other TDX sales team, and Canton was making a six-figure income.

“I killed that market,” he said.

He later became executive vice president at Allnet Communications and made $10 million when that company was sold. He was 36 at the time.

He joined Telco Communications in 1995 and was a top sales executive when Telco was sold to Excel Communications for $1.2 billion. It was another hit. He stayed for three years and left in 2000.

The outcome of iCore is still unwritten. It’s the telephone business, which Canton knows.

“Only an optimist would start an Internet phone company with their own money,” he says. “I am always the guy going against the brand.”

To keep his staff motivated, he is inculcating his sales philosophy in the company. He keeps employees motivated with bonus trips to resorts in the Bahamas or Cabo San Lucas in Mexico. Salespeople, under Canton-clone sales chief Michael Bertamini, can make up to $250,000 a year.

He keeps working because he does not take his millions for granted.

“When you are 13, and you see everything your parents work for go away, it makes it real. It makes you want to work so that you can hold on to it. Half the battle is getting it, the other half is holding on to it.”

And his health?

No worries there. He is gearing up for his fourth triathlon next week in Miami.