Tyco International Ltd., Hamilton, Bermuda, agreed to acquire the electronic security systems business of Cambridge Protection Industries LLC for about $1 billion.

Tyco said it plans to add Cambridge's network of more than 1 million mostly residential subscribers to its ADT Security Services unit, a part of the company's Fire & Security Services unit.

Cambridge Protection, Lisle, Ill., with about $525 million in annual sales, is one of the nation's largest providers of electronic security services. It provides services to residential, commercial and government customers throughout North America, primarily through its SecurityLink brand.

ADT currently has 3 million customers, also mostly residential. ADT accounted for about $2 billion of Tyco's $28.9 billion in revenue last year.

Tyco Chairman L. Dennis Kozlowski said the new security businesses are expected to “generate healthy organic growth with attractive incremental margins” and further the company's “strategy of expanding its base of recurring revenues.”

Maryanne Kane, Tyco's chief communications officer, said the acquisition is expected to close by early July.