It is more formal to go to China Mobile, China Unicom or China Telecom.
400 telephone numbers are divided into 4006 (China Unicom), 4007 (China Mobile's former China Railway Telecom), 4008 (China Telecom), 4001 (China Mobile's new number range), 4000 (China Unicom's new number range), 4009 (China Telecom’s new number section).
The 400 telephone is a nationwide virtual telephone switchboard with unified numbers specially designed for enterprises and institutions. All incoming calls to the 400 switchboard number will be forwarded to a preset landline, mobile phone or call number. Center online.
Extended information
When the company needs to change the company's original phone number due to relocation or other reasons, the 400 number does not need to be changed. It only needs to change the phone number bound to the 400 number. The business Never lost. The 400 number applied by an enterprise is the only virtual number in the country and can remain unchanged for life.
When the company moves (even across provinces), you only need to change the physical phone number (landline, mobile phone) bound to the 400 number. Old customers can still make calls as usual, and none of the customers will know how. It also saves you a lot of costs in reprinting promotional materials and the trouble of notifying old customers one by one.