What is the number one dual machine?

Shuanghua 1 is the post-paid ordinary fixed telephone number of China Telecom for the whole province. Prepaid fixed telephone and private network customers, public telephone, campus telephone and regional card telephone, No.1 dual-machine (Tianyi Edition) service and province-wide post-paid prepaid (OCS)CDMA number must belong to the same local network and have the same account name as the service number (fixed). Not open to prepaid (intelligent network), wireless public telephone and other CDMA numbers. One-machine-two-machine (Tianyi Edition) service is a service in which customers use fixed telephone numbers and voice and short messages for C network numbers. For more service benefits, click on "official website" customer service 36 below to answer your questions.