Baby monitors cause radio interference
In a case earlier this year, a water purification plant was unable to wirelessly receive data from a pump station in Kanagawa Prefecture because of interference caused by radio waves from a baby monitor.
According to the ministry, many of the 22 cases of radio interference occurred in Okinawa Prefecture, where many US military bases are located, as well as Kanagawa and Nagasaki prefectures. Monitors imported from the United States are believed to have caused radio interference. In some cases, trouble occurred at cell phone base stations and with radios used by parcel delivery companies.
Baby monitors, which parents can use to check on their babies from remote locations, and similar monitoring devices are popular in the United States and other countries.
Monitors produced in accordance with foreign standards are offered for sale on the Internet and are becoming widely used in Japan. However, some devices do not meet Japanese technical standards.
According to the Kanagawa prefectural government, the Samukawa water purification plant in Samukawa in the prefecture became unable to wirelessly receive data from a pump station in Kamakura, about 20 kilometers away, on Jan. 8.
The data, normally sent every 10 minutes, was needed to keep track of operating conditions and water levels at the pump station. The prefectural government reported the trouble to the ministry's Kanto Bureau of Telecommunications.
The bureau investigated the incident, and two months later it traced the interfering radio waves to a baby monitor installed in a house several hundred meters from the water purification plant.
Because the radio waves emitted by the monitor were 1,124 times stronger than the standard for weak radio waves, the bureau instructed the user to stop using the device, which was made in China.
Because the Radio Law does not regulate the importation or sale of the monitors, the bureau and the Kanagawa prefectural government have called on people to refrain from using monitors without a logo to certify the products meet Japanese standards. They also asked sellers of those monitors to refrain from selling them.
The Samukawa plant covers more than 100 unmanned pump stations and distribution reservoirs in the southern part of the prefecture, and uses automatic wireless communication to check on the operations.
Contact with the pump station that was affected by radio interference has since been switched from wireless communication to wire communication.
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