Sompong Assawaboonmee, manager of the telephone division of NT, said NT’s international line exchange facility has been equipped with a system to detect suspecting calls from abroad round the clock.
Sompong said if the system detects irregularity, the calls will be blocked and the operators of the blocked numbers would be alerted to check.
Sompong said most foreign calls from call-centre gangs had an irregular format and sometimes they called unusual destination numbers, such as unassigned numbers or numbers with space code.
He said a line that makes irregularly-repeated calls to the same destination number in a short time would also be blocked and investigated.
Sompong said the NT has been using the same format of international phone numbers with the ITU Telecommunication Standardisation Sector. The format starts with a “plus” sign and follows with the country code from where the calls are made.
He urged Thais to reject calls from countries where they do not have relatives or calls that do not follow the format of the ITU-T.
In case of suspicion, telephone users can call the NT Contact Centre 1888, he said.