It also ordered Clearinghouse Co, which handles the number transfers for all telecom operators, to expand capacity to 300,000 numbers per day within 30 days, up from 40,000 now.
Number portability enables mobile-phone customers to migrate to different networks and keep their existing phone numbers.
Last month there were only 80,000 number transfers, mainly for True Move customers switching to CAT Telecom’s cellular network.
Advanced Info Service (AIS) has migrated about a million of its users to its 2.1-gigahertz licence holder Advanced Wireless Network (AWN) via the call transit system. The NBTC is examining whether this method complies with regulations, said Korkij Danchaivichit, the commission’s deputy secretary-general.
Sutichai Chuenchoosil, senior vice president for business relations and development of AIS, said the firm had informed the NBTC that it had to use the call transit method in response to overwhelming demand of customers who want to move to AWN’s third-generation network, while waiting for the number-portability capacity of all cellular operators to be expanded. He added that AIS had given priority to serving the needs of customers.