Which of the following statements is NOT true（）
A. With VoIP technology, the phone caller's voice will be broken into pieces.
B. Different types of technology are accompanied with different advantages.
C. With VoIP technology, the quality of voice will always remain the same.
D. On the Internet, information will be broken into pieces and then connected again.
查看答案
So far, how many volumes of the book have been published（）
A. Five.
B. Four.
C. Three.
D. None.
Which of the following will affect the voice quality through Internet（）
A. The speed of your voice.
B. The speed of the Internet.
C. The Internet traffic.
D. The service of the operator.
某计算机IP地址为192.168.1.68，网关为192.168.1.254。该计算机现在无法访问IP地址为202.120.45.12的主机，若要测试该计算机在其网段内是否工作正常，应使用（）命令。
A. ping 192.168.1.254
B. ping 192.168.1.68
C. ping 202.120.45.12
D. ping 127.0.0.1
以下关于曼彻斯特编码的描述中，错误的是（）
A. 无需另外传输同步信号
B. 每个比特都由两个码元组成
C. 用电平跳变来区分0和1
D. 用电平的高低来区分0和1
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