The worsening cell-phone traffic jams have sparked calls for the telecommunications watchdog to supervise marketing and call promotion campaigns by mobile-phone operators.

Thapakorn Promsopa, 22, an engineering student at Khon Kaen University, is a typical disgruntled customer. "I have a lot of problems using my cell phone," he said. "Sometimes, I become so frustrated that I want to throw it away."

He said his problems usually arise between 7pm and 10pm.

"When I want to make a call, the cell phone too often tells me that its network is busy," Thapakorn said. As well, his calls are sometimes transferred to wrong numbers, despite having dialled correctly.

He called on relevant agencies to ensure a good standard of service for mobile-phone users.

Another Khon Kaen university student, Nattiyakorn Inthisaeng, said it had become very difficult to use mobile phones, particularly if she wanted to call someone using another network. "The services are very bad from 6pm to 10pm," she said.

Nattiyakorn said she partly solves the problem by keeping two SIM cards from different service providers.

 "When one of them doesn't work, I can try the other. It's also easier to reach people by calling them on the network they use. With SIM cards from two different operators, my chance of reaching others is higher," she said.

Chiang Mai University student Assarapak Panjaroen said cell-phone services were failing at night because there were so many users during this time - probably because of recently launched promotional packages. Cell-phone shop owner Ittirit Chunrat said customers now prefer to have two SIM cards to ensure they can make contact with others. "It becomes very difficult to connect with people on different service networks," he said.

Ittirit added that customers were showing immense interest in new promotional packages being offered by different mobile operators.

Meanwhile, the Office of the Consumer Protection Board is checking consumer complaints to see if any of them concern cell-phone service problems. "If there are complaints filed with us, we can take action," said deputy secretary-general Nirote Jaroenprakob.

He said the board could review the advertisements of mobile phone services and determine whether the operators have exaggerated the quality of service.

"If the services fall short of what they describe in their advertisements, the operators will face legal action," Nirote said.

National Telecommunications Commission (NTC) deputy secretary-general Manas Songsaeng said he intended to propose that the commission supervise the promotional packages offered by mobile phone service providers.

"The NTC should review these

packages before they are launched, to ensure that cell-phone users don't suffer any adverse impact," he said.

In related news, software being used by the AIS signalling gateway in Bangkok suffered a technical glitch at 11.45am yesterday. The problem took 90 minutes to solve.

During that time most AIS subscribers in Bangkok were unable to call out, but mobile phone users on other networks were still able to contact AIS subscribers.

AIS executive vice president for operations Wichian Mektrakarn denied that the technical problem stemmed from call congestion in the network caused by the company's heavy call promotions.

"It had nothing to do with call traffic," he said, adding that AIS had established a signalling gateway in each of the four regions of Thailand.