更多"DCD://Data Carder Detect，载波侦测指示，有时简"的相关试题:
[填空题]DCD://Data Carder Detect，载波侦测指示，有时简称CD(Cartier Detect)。当调制解调器收到对方调制解调器送来的信号(载波Carrier)时，此灯会亮，代表已能和对方调制解调器传送 【20】 。
[单项选择]
A （） is a data type whose major attributes are determined by the roles governing the insertion and deletion of its elements. The only element that can be deleted or removed is the one that was inserted most （） . Such a structure is said to have a last-in/first-out (LIFO) behavior, or protocol.
A （） is a data type whose major attributes are determined by the roles governing the insertion and deletion of its elements.
A. stack
B. queues
C. pointer
D. record
[单项选择]
在E1载波中，每个子信道的数据速率是（），E1载波的控制开销占（）。
E1载波的控制开销占（）。
A. 3.125%
B. 6.25%
C. 1.25%
D. 25%
[单项选择]
在E1载波中，每个子信道的数据速率是（），E1载波的控制开销占（）。
在E1载波中，每个子信道的数据速率是（）
A. 32kb/s
B. 64kb/s
C. 72kb/s
D. 96kb/s
[单项选择]在E1载波中，每个子信道的数据速率是 (16) ，E1载波的控制开销占 (17) 。
A. 32kbps
B. 64kbps
C. 72kbps
D. 96kbps
[填空题]到1990年，NSFNET的第二个主干网的速率已经提高到T1载波，T1载波的传输速率是（）。
[单项选择]
E1载波的数据速率是（45）Mb/s，T1载波的数据速率是（46）Mb/s。
46（）
A. 1.544
B. 2.048
C. 6.312
D. 8.448
[单项选择]
E1载波的数据速率是（45）Mb/s，T1载波的数据速率是（46）Mb/s。
45（）
A. 1.544
B. 2.048
C. 6.312
D. 8.448
[单项选择]The Environmental Protection Agency unveiled a detailed proposal Wednesday for using the government’s regulatory powers to curb greenhouse gas emissions—reassuring foreign allies of the U.S. commitment to fight climate change and warning Congress that the administration will act on its own if lawmakers fail to address the issue. The rules would force new or substantially modified industrial plants emitting at least 25,000 tons of greenhouse gases a year to employ "best available control technologies and energy-efficiency measures" to minimize emissions.
The agency unveiled its proposal hours after Senate Democrats introduced their version of the global warming bill that passed the House in June, and as international climate negotiators gathered in Bangkok, Thailand, to prepare for global warming treaty talks in Copenhagen in December. The EPA and Senate actions stoked(激起 ) optimism among environmentalists and others. Some had voiced concern that reaching agreement in Copenhagen
A. The Senate failed to carry out reaching agreement in Copenhagen.
B. The United States is not prepared to take measures.
C. The United States forces the developing countries to take steps.
D. The EPA will not just wait for government’s decision to carry out action.
[单项选择]A certain airport security scanner designed to detect explosives in luggage will alert the scanner’s operator whenever the piece of luggage passing under the scanner contains an explosive. The scanner will erroneously alert the operator for only one percent of the pieces of luggage that contain no explosives. Thus in ninety-nine out of a hundred alerts explosives will actually be present.
The reasoning in the argument is flawed because the argument
A. ignores the possibility of the scanner’s failing to signal an alert when the luggage does contain an explosive.
B. draws a general conclusion about reliability on the basis of a sample that is likely to be biased.
C. ignores the possibility of human error on the part of the scanner’s operator once the scanner has alerted him or her.
D. fails to acknowledge the possibility that the scanner will not be equally sensitive to all kinds of explosives.
E. (E) substitutes one group for a different group in the statement of a percentage.
[简答题]The basic structure of biological membranes is determined by the lipid bilayer, but their specific functions are carried out largely by proteins. Explain your answer.
