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Smoulder holder

发布时间:2019-03-08 05:14:03来源:未知点击:

By Barry Fox LAPTOP users risk the destruction of their modems if they plug them into phone sockets in hotel rooms. Modern hotels often use digital switchboards to route and bill calls, but if a conventional analogue modem is plugged into a digital line it will not only fail to work, but the higher current—up to 0.5 amps—will quickly burn it out. Now American Power Conversion of West Kingston, Rhode Island, has developed the SurgeArrest, a $40 connector that plugs between a laptop and its mains adapter, and between the phone line and modem. The mains adapter provides power for sensor circuitry inside the connector. As soon as this detects a current of more than 140 milliamps on the phone line it lights a warning lamp, and at 200 milliamps it breaks the connection to the modem. The device goes on sale in Europe next year. Meanwhile, Konexx of San Diego, California, goes one stage further with its new $200 AutoSet adapter. This exploits the fact that all phones, whether digital or analogue, send an analogue signal to their handset. The Autoset plugs in between the main body of the phone and the handset and relies on a digital-to-analogue converter inside the digital phone to provide a safe working connection for an analogue modem. Because the level of the analogue signal flowing between the phone and handset can vary considerably between different phone types,