相关试题
【单选题】
20TTL电路在正逻辑系统中，以下各种输入中___相当于输入逻辑“0”。
A. 悬空
B. 通过电阻2.7kΩ接电源
C. 通过电阻2.7kΩ接地
D. 通过电阻510Ω接地
【单选题】
21对于TTL与非门闲置输入端的处理，不可以___。
A. 接电源
B. 通过电阻3kΩ接电源
C. 接地
D. 与有用输入端并联
【单选题】
22STTL数字集成电路与CMO数字集成电路相比突出的优点是___。
A. 微功耗
B. 高速度
C. 高抗干扰能力
D. 电源范围宽
【单选题】
23以下式子中正确的是___
A. 1+A＝A
B. A＋A=1
C. A•A＝1
D. A+AB=A
【单选题】
在一个四变量逻辑函数中，___为最小项。
【单选题】
A+BC=___。
A. A+B
B. A+C
C. （A+B）（A+C）
D. B+C
【单选题】
26以下代码中为无权码的为___。
A. 5421BCD码
B. 8421BCD码
C. 余三码
【单选题】
一位十六进制数可以用___位二进制数来表示。
【单选题】
28十进制数25用8421BCD码表示为___。4位
A. 10 101
B. 0010 0101
C. 100101
D. 10101
【单选题】
29与十进制数（53.5）10不等值的数或代码为___。
A. (0101 0011.0101)8421BCD
B. (35.8)16
C. (110101.1)2
D. (60.4)8
【单选题】
30与八进制数(47.3)8等值的数为___
A. (100111.011)2
B. (97.3)16
C. (27.3 )16
D. (100111.11)2
【单选题】
31下列各型号中属于优先编码器是___。
A. 74LS85
B. 74LS138
C. 74LS148
D. 74LS48
【单选题】
七段数码显示器BS202是___。
A. 共阳极LED管
B. 共阴极LED管
C. 共阳极LCD管
D. 共阴极LCD管
【单选题】
33八输入端的编码器按二进制数编码时，其输出端的个数是___。
【单选题】
四输入的译码器，其输出端最多为___。
A. 4个
B. 8个
C. 10个
D. 16个
【单选题】
当74LS148的输入端按顺序输入11011101时，输出为___。
A. 101
B. 010
C. 001
D. 110
【单选题】
用三线-八线译码器74LS138和辅助门电路实现逻辑函数Y=a2+a1a2，应___。
A. 用与非门，Y=y0y1y4y5y6y7
B. 用与门，Y=y2y3
C. 用或门，Y=y2+y3
D. 用或门，Y=y0+y1+y4+y5+y6+y7
【单选题】
37时序逻辑电路中一定包含___。
A. 触发器
B. 组合逻辑电路
C. 移位寄存器
D. 译码器
【单选题】
仅具有置“0”和置“1”功能的触发器是___。
A. 基本RS触发器
B. 钟控RS触发器
C. D触发器
D. JK触发器
【单选题】
由与非门组成的基本RS触发器不允许输入的变量组合为___。
【单选题】
40仅具有保持和翻转功能的触发器是___。
A. JK触发器
B. T触发器
C. D触发器
D. T' 触发器
【单选题】
触发器由门电路构成，但它不同于门电路功能，主要特点是___。
A. 具有翻转功能
B. 具有保持功能
C. 具有记忆功能
【单选题】
TTL集成触发器直接置0端[]和直接置1端[]在触发器正常工作时应___。
A. =1，=0
B. =0，=1
C. 保持高电平“1”
D. 保持低电平“0”
【单选题】
按逻辑功能的不同，双稳态触发器可分为___。
A. RS、JK、D、T等
B. 主从型和维持阻塞型
C. TTL型和MOS型
D. 上述均包括
【单选题】
同步计数器和异步计数器比较，同步计数器的显著优点是___。
A. 工作速度高
B. 触发器利用率高
C. 电路简单
D. 不受时钟CP控制。
【单选题】
把一个五进制计数器与一个四进制计数器串联可得到___进制计数器。
【单选题】
下列逻辑电路中为时序逻辑电路的是___ 。
A. 变量译码器
B. 加法器
C. 数码寄存器
D. 数据选择器
【单选题】
47N个触发器可以构成最大计数长度{进制数}为___ 的计数器。
【单选题】
N个触发器可以构成能寄存___位二进制数码的寄存器。
【单选题】
49五个D触发器构成环形计数器，其计数长度为___。
【单选题】
同步时序电路和异步时序电路比较，其差异在于后者___。
A. 没有触发器
B. 没有统一的时钟脉冲控制
C. 没有稳定状态
D. 输出只与内部状态有关
【单选题】
一位8421BCD码计数器至少需要___个触发器。
【单选题】
某电视机水平-垂直扫描发生器需要一个分频器将31500HZ的脉冲转换为60HZ的脉冲，欲构成此分频器至少需要___个触发器。
A. 10
B. 60
C. 525
D. 31500
【单选题】
555定时器属于___
A. 时序逻辑电路
B. 组合逻辑电路
C. 模拟电子电路
【单选题】
54多谐振荡器可产生 ___
A. 正弦波
B. 矩形脉冲
C. 三角波
D. 锯齿波
【单选题】
脉冲整形电路有___。
A. 多谐振荡器
B. 施密特触发器
C. 555定时器
【单选题】
56石英晶体多谐振荡器的突出优点是___ 。
A. 速度高
B. 电路简单
C. 振荡频率稳定
D. 输出波形边沿陡峭
【单选题】
TTL单定时器型号的最后几位数字为___。
A. 555
B. 556
C. 7555
D. 7556
【单选题】
555定时器不可以组成___。
A. 多谐振荡器
B. 单稳态触发器
C. 施密特触发器
D. JK触发器
【单选题】
59以下各电路中，___可以产生脉冲定时。
A. 多谐振荡器
B. 单稳态触发器
C. 施密特触发器
D. 石英晶体多谐振荡器
推荐试题
【单选题】
Which user authentication method is used when users login to the Clientless SSLVPN portal using https://209.165.201.2/test？___
A. AAA with LOCAL database
B. AAA with RADIUS server
C. Certificate
D. :Both Certificate and aaa with LoCAL database
E. Both Certificate and AAA with RADIUS server
【单选题】
What' s the technology that you can use to prevent non malicious program to runin the computer that is disconnected from the network？___
A. Firewall
B. Sofware Antivirus
C. Network IPS
D. Host IPS
【单选题】
Which statement about the communication between interfaces on the same security level is true？___
A. Interfaces on the same security level require additional configuration to permit interinterface communication
B. Configuring interfaces on the same security level can cause asymmetric routing
C. All traffic is allowed by default between interfaces on the same security level
D. You can configure only one interface on a n individual security level
【单选题】
Which product can be used to provide application layer protection for tcp port 25 traffic？___
A. ESA
B. CWS
C. WSA
D. ASA
【单选题】
which iPS mode is less secure than other options but allows optimal network through put ?___
A. inline mode
B. inline-bypass mode
C. transparent mode
D. Promiscuous mode
【单选题】
Which feature of the Cisco Email security Appliance can mitigate the impact of snowshoe spam and sophisticated phishing attack？___
A. reputation based filtering
B. signature based IPS
C. contextual analysis
D. graymail management and filtering
【单选题】
Which type of social-engineering attack uses normal tele phone service as the attack vector？___
A. smishing
B. dialing
C. phishing
D. vishing
【单选题】
Which quantifiable item should you consider when you organization adopts new technologies？___
A. exploits
B. vulnerability
C. threat
D. Risk
【单选题】
Referencing the ClA model， in which scenario is a hash- only function most appropriate ？___
A. securing data at rest
B. securing real-time traffic
C. securing data in files
D. securing wireless transmissions
【单选题】
Which ports must be open between a aaa server and a microsoft server to permit Active Directory authentications？___
A. 445 and 389
B. 888 and 3389
C. 636 and 4445
D. 363 and 983
【单选题】
Refer to the exhibit for which reason is the tunnel unable to pass traffic___
A. the tunnel is failing to receive traffic from the remote peer
B. the local peer is unable to encrypt the traffic
C. the ip address of the remote peer is incorrect
D. UDP port 500 is blocked
【单选题】
Which type of attack can exploit design flaws in the implementation of an application without___
A. DHCP starvation attacks
B. low-rate dos attacks
C. application DDos flood attacks
D. application DDoS flood attacks
E. volume-based DDoS attacks
【单选题】
How can you protect CDP from reconnaissance attacks？___
A. Enable dynamic ARP inspection on all untrusted ports.
B. Enable dot1x on all ports that are connected to other switches.
C.
D. isable CDP on ports connected to endpoints.
【单选题】
Which type of attack can exploit design flaws in the implementation of an application without ？___
A. DHCP starvation attacks
B. low-rate dos attacks
C. application DDos flood attacks
D. application DDoS flood attacks
E. volume-based DDoS attacks
【单选题】
Which option is a key security compone nt of and MDM deployment ？___
A. using network-specific installer packages
B. using an application tunnel by default
C. using self-signed certificates to validate the server
D. using MS-CHAPv2 as the primary
E. AP method
【单选题】
Which Firepower Management Center feature detects and block exploits and hack attempts？___
A. Content blocker
B. file control
C. intrusion prevention
D. advanced malware protection
【单选题】
hich description of the nonsecret numbers that are used to start a Diffie- Hellman exchange is ture？___
A. They are preconfigured prime integers.
B. They are large pseudorandom numbers.
C. They are very small numbers chosen from a table of known valuses
D. They are numeric values extracted from ha shed system hostnames
【多选题】
Which two characteristics of an application layer firewall are true？___
A. provides stateful firewal functionality
B. has low processor usage
C. provides protection for multiple applications
D. provides rever se proxy services
E. is immune to URL manipulation
【多选题】
Which two devices are components of the BYOD architectural framework？___
A. Nexus 7010 switch
B. Cisco 3945 Router
C. Identify Services Engine
D. Wireless Access oints
E. Prime Infrastructure
【多选题】
Which two actions can a zone based firewall take when looking at traffic？ ___
A. forward
B. inspect
C. drop
D. broadcast
E. filter
【多选题】
n which two situations should you use in-band management？___
A. when management applications need concurrent access to the device
B. when you require administrator access from multiple locations
C. when a network device fails to forward packets
D. when you require ROMMON access
E. when the control plane fails to respond
【多选题】
What are two ways to prevent eavesdropping when you perform device management tasks？___
A. Use an SSH connection.
B. Use SNMPv3
C. Use out-of-band management
D. Use SNMP
E. Use in-band management
【多选题】
Which two features are commonly used CoPP and CPPr to protect the control plane？ ___
A. QoS
B. traffic classification
C. access lists
D. policy maps
E. class maps
F. Cisco Express Forwarding
【多选题】
Which four tunne ling prot ocols are enabled in the Dfit GrpPolicy group policy ？___
A. Clientless SSL VPN
B. SSL VPN Client
C. PPTP
D. L2TP/IPsec
E. IPsec IKEv1
F. IPsec IKEv2
【多选题】
Which two statements regarding the aSA VPN configurations are correct？___
A. The asa has a certificate issued by an external certificate authority associated to the ASDM TrustPoint1
B. The Default WEBVPNGroup Connection Profile is using the aaa with RADIUS server method
C. The Inside-srvbook mark references the https://192.168.1.2url
D. Only Clientless SSL VPN access is allowed with the Sales group policy
E. Any Connect， IPSec IKEv1， and IPSec IKEv2 VPN access is enabled on the outside interface
F. The Inside -SRV bookmark has not been applied to the Sales group policy
【多选题】
Which three ESP fields can be encrypted during transmission？___
A. Security Parameter Index
B. Sequence Number
C. MAC Address
D. Padding
E. Pad length
F. Next Header
【多选题】
.Which three statements de scribe DHCP spoofing attacks？___
A. They can modify traffic in transit.
B. They are used to perform man- in-the-middle attacks
C. They use ARP poisoning
D. They can access most network devices
E. They protect the ide ntity of the attacker by masking the DHCP address.
F. They are can physically modify the network gateway.
【多选题】
Which statement about the communication between interfaces on the same security level is true？___
A. Interfaces on the same security level require additional configuration to permit interinterface communication
B. Configuring interfaces on the same security level can cause asymmetric routing
C. All traffic is allowed by default between interfaces on the same security level
D. You can configure only one interface on a n individual security level
【多选题】
In which two situations should you use in band management？ ___
A. when the control plane fails to respond
B. when you require administrator access from multiple locations
C. when you require ROMMON access.
D. where a network device fails to forward packets
E. when multiple ma nagement applications need concument access to the device.
【多选题】
Which two features are supported in a VRF-aware softwar infrastructure before VRF-lite?___
A. multicast
B. fair queuing
C. WCCP
D.
E. IGRP
【多选题】
.Which loS command do you enter to test authentication again a AAA server？___
A. dialer aaa suffix <suffix> password <password>
B. ppp authentication chap pap test
C. test aaa-server authentication dialer group user name <user> password <password>
D. aaa authentication enable default test group tacases
【多选题】
Which two statements about the self zone on a cisco Xone based policy firewall are true？___
A. Multiple interfaces can be assigned to the self zone
B. it supports stateful inspections for multicast traffic
C. zone pairs that include the self zone apply to traffic transiting the device.
D. it can be either the source zone or the destination zone
E. traffic entering the self zone must match a rule
【多选题】
Which type of attack can exploit design flaws in the implementation of an application without ？___
A. DHCP starvation attacks
B. low-rate dos attacks
C. application DDos flood attacks
D. application DDoS flood attacks
E. volume-based DDoS attacks
【单选题】
Which type of firewall can server as the interme diary between a client and a server ?___
A. Stateless firewall
B. application firewall
C. proxy firewall
D. personal firewall
【单选题】
What is the highest security level that can be configured for an interface on an ASA？___
【单选题】
Which term refers to the electromagnetic interference that can radiate from network cables？___
A. Gaussian distributions
B. Doppler waves
C. emanations
D. multimode distortion
【单选题】
How does a zone pair handle traffic if the policy de fination of the zone pair is missing?___
A. It inspects all traffic.
B. It drops all traffic.
C. It permits all traffic wihtout logging
D. It permits and logs all traffic
【单选题】
default how does a zone based firewall handle traffic to add from the self zone？___
A. It permits all traffic without inspection
B. It inspects all traffic to determine how it is handled
C. It permits all traffic after inspection
D. It frops all traffic
【单选题】
Which command should beused to ena ble AAA Authentication to determine if a user can access the privilege command level？___
A. aaa authentication enable local
B. aaa authentication enable level=
C. aaa authentication enable method de fault
D. aaa authentication enable defa ult local
【单选题】
On an ASA， the policy indicates that traffic should not be translated is often referred to as which of the following？___
A. NAT zero
B. NAT forward
C. NAT nul
D. NAT allow
