400电话的起源与发展

The origin and development of 400 telephone

400电话是之前企业常用的800电话的一个升级版本。目前中国的400业务有三大运营商，分别是：电信、联通、移动。其中电信的400业务（4008号段）发展最早，后来中国电信网通分家后，加上铁通脱离铁道部，原4008所有号码归中国电信所有，中国网通和铁通分别启用4006、4007新号段。

The 400 phone is an upgraded version of the previous 800 phone calls used by the enterprise. At present, there are three major operators in China's 400 business, which are Telecom, Unicom and mobile. Among them, the 400 business of Telecom (No. 4008) was the earliest developed. Later, after the separation of China Telecom Netcom and Tietong from the Ministry of railways, all 4008 of the original 4008 were owned by China Telecom. China Netcom and Tietong set up 4006 and 4007 new segments respectively.

最早400电话一般电一般不提供平台，绑定号码只能是本地固定电话，不能转接手机和外地固定电话，查询话费绑定号码等需要去营业厅办理。

The first 400 phone calls usually do not provide a platform. The binding number can only be local fixed telephone, and cannot transfer to mobile phones and field fixed telephone, inquire the telephone fee, bind number and so on, so we need to go to the business hall.