400电话是唯一号码
400 is the only number
一个400号码可以绑定是10个以上的固定电话、手机或呼叫中心专线号码，所以企业只需公布全国唯一的400号码，统一宣传，简单易记。当用户拨打400号码，即可根据企业的设置，将来电转接到不同号码上，客户记住了400号码，就等于记住了企业。例如麦当劳订餐热线4008-517-517因谐音“我要吃”而深入人心，不法分子即使想要假冒也很难。
A 400 number can be bound to more than 10 fixed telephone, mobile phone or call center line numbers, so enterprises only need to publish the country's only 400 number, unified publicity, easy to remember. When the user dials 400 number, he can transfer the electricity to different numbers according to the setting of the enterprise. If the customer remembers the 400 number, he will remember the enterprise. For example, McDonald's ordering hotline 4008-517-517 is popular because of its homophonic "I want to eat". It is difficult for criminals to fake it even if they want to.