BOSTON (Bloomberg) - Tyco International Ltd., the world's biggest maker of security systems, agreed to buy the security unit of Toronto-based FirstService Corp. for about $187 million to boost sales in the banking and energy markets.

FirstService Security had more than $200 million in revenue in the past 12 months and employs about 2,400 people with 17 offices in the US and Canada, Tyco said yesterday in a statement.

Tyco cited higher sales at the ADT security systems unit when it raised its 2008 revenue and profitability forecasts in January. The ADT unit provided more than 40 percent of the Bermuda-based company's revenue last fiscal year. The purchase allows Tyco to add FirstService's SST brand in the US and Intercon in Canada and provides growth opportunities in commercial markets.

ADT posted $7.65 billion in sales in the year ended in September and has 60,000 employees worldwide, with 22,000 in North America. Both companies' boards have approved the transaction, FirstService said in a statement.

FirstService said it is selling the unit to focus on its real estate service operations. Tyco, run from West Windsor, New Jersey, rose 22 cents to $44.50 at 4.15pm in New York Stock Exchange composite trading. FirstService rose 40 cents to C$24.10 in Toronto.

• Tyco International Finance SA's (TIFSA) $1 billion commercial paper programme has been assigned an 'A-2' rating by Standard & Poor's (S&P) Ratings Services, while Fitch assigned it an 'F2' rating.

S&P said the ratings reflect the company's strong business profile - which includes certain leading market positions, along with product, market, and geographic diversity and substantial recurring service-oriented revenues - and intermediate financial profile, which includes moderate financial leverage.

Fitch said its ratings reflected its belief that Tyco will continue to maintain solid financial measures in support of its operating and financial strategies.