Chris Harry is a model employee for the US call centre industry. The 25-year-old arrives promptly at his cubicle, speaks courteously on phone and is never late or absent.He plans to stick with his job for three years, a boon in an industry plagued by high turnover. And he gladly works for money many Americans would scoff at — $130 or so a month. After all, he could be back swabbing cell block floors for a third of that.‘‘I can’t complain about fair,’’ said Harry, sentenced to 10 years and eight months for robbery. ‘‘At least I’m not wearing a ball and chain.’’Prison inmates like Harry are the reason Perry Johnson Inc., a Southfield, Michigan-based consulting company, chose to remain in the United States rather than join a host of telemarketing companies moving offshore.Perry Johnson had intended to move to India. But the company chose instead to open inside Snake River Correctional Institution, a sprawling razor wire and cinder block state penitentiary a few miles west of the Idaho line.The centre’s opening followed a year-long effort by the Oregon Department of Corrections to recruit businesses that would otherwise move offshore, and echoes a national trend among state and federal prisons.‘‘This is a niche where the prison industry could help the US economy,’’ said Robert Killgore, Director of Inside Oregon Enterprises, the quasi-state agency that recruits for-profit business to prisons. ‘‘I’m really excited about this,’’ he said. ‘‘We keep the benefits here in the US with companies where it’s fruitless to compete on the outside.’’Perry Johnson Inc. opened its call centre in an Oregon prison for half the price of relocating to India, and achieved many of the same benefits, according to Mike Reagan, Director of Inside Oregon Enterprises at Snake River. The only pre-requisite: inmates must have three to five years remaining on their sentence.