Q. Which of the following statement is incorrect?
A.  The CCITT Recommendation X.25 specifies three layers of communication: physical, link and network. B.  The second layer of communication is the data-link layer C.  Errors in the physical layer can be detected by the data link layer D.  The fourth layer, in reference to the OSI model, is the session layer E.  None of the above
Similar Questions
1. Protocols are
A.  Agreements on how communication components and DTE B.  Logical communication channels used for transferri C.  Physical communication channels used for transferr D.  None of the above
2. The method of communication in which transmission takes place in both directions, but only one direction at a time is called
A.  Simplex B.  Four wire circuit C.  Full Duplex D.  Half Duplex
3. Error detection at the data link level is achieved by
A.  Bit Stuffing B.  Cyclic Redundancy Code C.  Hamming Code D.  Equalization
4. Which of the following is a wrong example of network layer?
A.  Internet Protocol (IP) - ARPANET B.  X.25 Packet Level Protocol (PLP)-ISO C.  Source routing and domain naming-USENet D.  X.25 level 2-ISO
5. The topology with highest reliability is:
A.  Bus topology B.  Star topology C.  Ring topology D.  Mesh topology
6. "BAUD" rate means
A.  The number of bits transmitted per unit time. B.  The number of bytes transmitted per unit time. C.  The rate at which the signal changes. D.  None of the above
7. Start and stop bits are used in serial communication for
A.  Error detection B.  Error correction C.  Synchronization D.  Slowing down the communication
8. Unmodulated signal coming from a transmitter is know as
A.  Carrier signal B.  Baseband signal C.  Primary signal D.  None of these
9. How many Character per sec(7bits + 1parity) can be transmitted over a 2400 bps line if the transfer is synchronous (1 "Start" and 1 "stop" bit)?
A.  300 B.  240 C.  250 D.  275
10. Which one of the following network uses dynamic or adaptive routing?
A.  TYMNET B.  ARPANET C.  SNA(IBM's System Network Architechture) D.  None of these
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