The national telecom regulator is forcing all mobile operators to remove the word "unlimited" from their data plans in order to address misleading and deceptive marketing practices in mobile data services.
Starting next Sunday, the five major mobile operators — AIS, DTAC, True Move, TOT Plc and CAT Telecom — must delete the word to ensure customers understand they will be paying for the speed that they buy a data plan for, said Takorn Tantasith, secretary-general of the National Broadcasting and Telecommunications Commission (NBTC).
Customers often experience slowdowns of downloads based on contracts they believed were for unlimited data service.
Mobile operators generally implement a "fair use" policy that effectively caps the amount of data a customer can download. Operators substantially reduce the speed of their services if customers go over certain fixed limits in a 30-day period.
Mr Takorn said the five operators had agreed to comply with the NBTC's order after meeting with the regulator yesterday.
The operators also insist they charge customers based on "actual use" for data services, calculating on a per-kilobyte basis, he said.
Operators deny allegations of charging customers on a per-megabyte basis.
"Internet data-use charges are different from those for voice. We earlier found the five major mobile operators charged customers on a per-minute basis instead of per second," Mr Takorn said.
On Jan 8, the NBTC ordered mobile operators to start charging customers on a per-second basis for some new promotional packages from March 1.
AIS, DTAC and True Move started some of their voice service promotional packages on a per-second basis last week.
Mr Takorn said operators were also obliged to deliver third-generation (3G) service at a minimum download speed of 345 kilobits per second and 153 Kbps for uploads, in compliance with the NBTC's licence requirements.
The regulator has identified the new 3G standard service contracts for operators, which require that average 3G tariff prices for both voice and data be reduced by at least 15% from the 2G service rates as of Dec 7, 2012.