Beijing subway safe from Wi-Fi router signals (2)

An operator at the Shenzhen Metro's hotline said the reason for the subway signal problem was still under investigation, and she has not received any notice to warn passengers not to bring any wireless equipment on the trains.

But experts in Beijing believe Wi-Fi signals could pose a threat to the operation of subway trains.

Zhao Da, section director of Beijing Radio Administration Bureau, said that the subway's control signal and the Wi-Fi signal are on the same spectrum.

"So it is possible to affect the subway's control signal although the subway's signal is coded," Zhao said.

Cellphone 3G signals will not affect the subway's signal, as they use a different frequency, he said.

Zhao suggested wireless routers should not be used on trains for safety.