● (71) In the strength of the carrier signal is varied to represent binary 1 or 0. (72) is

Question

● (71) In the strength of the carrier signal is varied to represent binary 1 or 0．

(72) is a system that can map a name to an address and conversely an address to an name．

(73) is a three-way handshaking authentication protocol that it's packets are encapsulated in the point-to-point protocol

(74) is an approach that enables an ATM Switch to behave like a LAN switch．

(75) is an guided media which is made of glass or plastic and transmits signals in the form. of light．

(71) A．ASK

B．PSK

C．FSK

D．FDM

(72) A．NAT

B．NCP

C．DDN

D．DNS

(73) A．PPP

B．PAP

C．CHAP

D．LCP

(74) A．VLAN

B．LANE

C．VPN

D．IPOA

(75) A．Coaxial cable

B．Optical fiber

C．Unshielded Twisted-pair Cable

D．Shielded Twisted-pair Cable

Answer 1

正确答案：A,D,C,B,B
【解析】在幅频键控(ASK)调制中，载波的振幅随所表示的0、1变化；DNS是一种能够将名字映射为IP地址同时也可以将IP地址映射为名字的系统；CHAP是一种利用三次握手机制的认证协议，它的数据包被封装在点对点链路协议上：LANE是一种能够让ATM交换机象局域网交换机一样的方式；光纤是一种用玻璃纤维和塑料外套制成的传输介质，它上面以光的形式来传输信号。