从本质上来讲，这些设备只不过是安装了特殊视频卡的Windows XP系统。

Essentially, these devices are nothing more than Windows XP systems with a special video card installed.

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安装在不同地点的摄像头通过电缆连接到视频卡，然后拦截到的图像或视频被存储到系统的大硬盘上。

Cables run from cameras mounted in various locations to that video card, and the captured images or video is then stored on the system's massive hard disks.

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如果使用比较旧的内核，那么必须安装video4linux软件，然后才能使用视频卡。

If you are using an older kernel, you have to install the video4linux software before your video capture will work.

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