400电话是由一个10位数字组成的号码，是电信运营商专为企业事业单位设计的，强大的虚拟电话总机，所有拨打400电话总机的来电均被转接至预先的实体电话（座机、手机）上接听，实现企业对外宣传统一性、规范性。
400 telephone is a 10-digit number, which is designed by telecom operators for enterprises and institutions. It is a powerful virtual telephone switchboard. All calls calling 400 telephone switchboard are transferred to the pre-emptive physical telephone (landline, mobile phone) to receive, so as to achieve the unity and standardization of enterprise external propaganda.
400电话话费由企业和拨打400电话的用户分摊，用户无需支付长途费用，体现了企业用户至上的服务意识，也是企业信誉和实力的象征。不仅仅提升企业的形象，更是企业经营理念的提升，400号码简单易记、话费分摊，同样是广告的投放，用户更愿意拨打400电话，有效增加来电数量以及沟通时间，广告投放效果提升30%以上。
The cost of 400 telephone calls is shared by enterprises and users who dial 400 telephone calls. Users do not need to pay long-distance fees. This reflects the service consciousness of enterprise users first, and also symbolizes the credibility and strength of enterprises. Not only to enhance the image of the enterprise, but also to enhance the business philosophy of the enterprise. 400 numbers are easy to remember and cost-sharing. It is also the placement of advertising. Users are more willing to dial 400 phone calls, effectively increase the number of calls and communication time, and the effect of advertising placement is improved by more than 30%.