The nation's leading mobile phone operator Chunghwa Telecom Co (中華電信) yesterday warned the public to be aware of excess charges on their cellphone bills.
The company made the statement after the circulation of an e-mail that offers for sale a device that can copy mobile phone Subscriber Identity Number (SIM) cards.
A SIM card is a chip that acts as a mobile phone's control center, storing the owner's passwords, communication records and phone lists.
"Access to SIM-card data means others can make phone calls and then put the charge on your bills," Chunghwa's chief engineer Shih Mu-piao (石木標) said.
"If consumers notice that their phone bills jump significantly, they might have been charged for phone calls by dishonest people," he added.
The trick works like this: first the device (a so-called SIM-card writer) is connected to a computer, and then users can run the software to copy all data from one SIM card to another.
According to Shih, the card writers were priced at NT$3,500 in the circulated e-mail -- and blank SIM cards sell for NT$2,500 each.
While selling these copying gadgets isn't against the law, using fake cards to make calls is absolutely illegal.
"They are not only sold on the Web, I know an increasing number of mobile phone retailers are beginning to put the device on their shelves," said Huang Wan-fa (
"Illegal users will be fined up to NT$1.5 million or sentenced for up to five years in prison," he added.
However, both Chunghwa Te-lecom and Huang said that the situation is under control.
"So far we didn't get any report from consumers regarding the use of fake SIM cards," Huang said.
Chunghwa's Shih said that, because unscrupulous people can't make copies unless they obtain the original cards, "the chances of getting over-billed is limited as long as users keep their SIM cards with them."
Users should also not leave their SIM cards with others and be sure to take their SIM cards out when they send their mobile phones in for repairs.
Meanwhile, a member of the Consumer Foundation (消基會) expressed worry over the new practice.
"This can be yet another headache after the fake credit card crisis," said attorney Joann Su (蘇錦霞), a member of the foundation's business committee.
Credit card fraud topped the foundation's complaints list last year, with more than 200 disputes reported to the committee.
She also asked the mobile service company to protect consumers.
"For example, users should insist on further investigation of excess phone charges before paying it."
In addition, operators should try to upgrade their SIM-card technology to avoid illegal usage, Su said.