Gatekeeper is a kind of security service. Every project of our company requires entrance guards to be familiar with the relevant skills and knowledge. First, they can check the certificates of entry and exit personnel and vehicles. They can register vehicles and articles according to regulations and receive visitors. Second, they can direct and guide personnel and vehicles. They can find certificates and vehicles. Abnormal conditions of entry and exit personnel, vehicles and carrying articles can be reported in time. Finally, the alarm signal can be identified and alarmed by common alarm devices such as intercom, telephone, wired and wireless buttons, keyboard and so on. Guarding the first hurdle of entry is the best embodiment of customer service.