In order to improve the ringing method of telephone used in power systems, a type of selective calling device using audio frequency has been developed.

为了使电力系统通信设备的呼叫装置更加使用方便工作可靠，我们研制了以按键电话机发出双音频呼叫信号进行选择接收的音频选号装置。

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After the device file is successfully opened by calling open , this parameter could be acquired.

通过调用open成功打开设备文件之后，将需要获取这个参数。

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We then loop, rescanning the SCSI bus (by echoing a command to a special file in the /proc pseudo-filesystem and calling devfsd) until the root device (/dev/sda1 in my case) is present.

然后我们进行循环，重新扫描 SCSI 总线（通过将命令回送到 /proc pseudo-filesystem 中的特殊文件，并调用 devfsd ），直到出现根设备（我的例子中为 /dev/sda1）。

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This is one of the advantages of being the first to offer built-in hands-free calling on a navigation device.

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Sprint offers Truly UnlimitedSM 4G LTE data, text and calling to any mobile device with no metering, no throttling, and no overages, all while on the Sprint network, making it the ideal carrier for customers who want to use every single feature of their Galaxy S 4 every single day of the month without worry.

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The devices work well, but they're expensive and require the person you're calling to have a matching device.

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