400 phone is a master called sharing services, namely, local telephone access charges borne calling, called to bear all costs of incoming calls. Has been widely used for pre-service consulting industries. 400 phone into 4006 (China Unicom), 4007 (China Mobile, former CRC), 4008 (China Telecom), 4001 (China Mobile new number section), 4000 (China Unicom's new number section), 4009 (China Telecom new number section) . 400 calls within specially designed for enterprises and institutions nationwide unified virtual telephone switchboard number, all dialed calls to the switchboard number 400 are forwarded to the pre-set fixed telephone, mobile or call center line. 400 telephone switchboard is only responsible for handling incoming calls, not outbound. Calls from businesses and call 400 telephone users share, call party to pay only local city calls. 400 hotline reflects the business sense of service, is a symbol of prestige and power.