US Patent 7591669 Board-to-board connector

A board-to-board connector adapted to be mounted to a printed circuit board includes a housing and at least one row of terminals. The housing defines at least one longwise row of cavities and at least one checking window extending longwise adjacent the row of cavities and penetrating the housing. The terminals are received in the corresponding cavities. Each of the terminals has a soldering portion adapted for being soldered to the printed circuit board. The soldering portions stretch into the corresponding checking window so as to check the solderability thereof with the printed circuit board in order to ensure that the terminals are soldered to the printed circuit board firmly.