In preparation for the Beijing Olympics and a series of other international events, some American companies are helping the Chinese government design and install one of the most comprehensive high-tech public surveillance systems in the world. When told of the companies’ transactions, critics of China’s human rights record said the work violated the spirit of a sanctions law Congress passed after the Tiananmen Square killings. The Commerce Department, however, says the sophisticated systems being installed, by companies like Honeywell, General Electric, United Technologies and I.B.M., do not run afoul of the ban on providing China with “crime control or detection instruments or equipment.” But the department has just opened a 45-day review of its policies on the sale of crime-control gear to China.