1. What is the main difference between DDCMP and SDLC?
a) DDCMP does not need special hardware to final the beginning of a message
b) DDCMP has a message header
c) SDLC has a IP address
d) SDLC does not use CRC

2. A band is always equivalent to?
a) a byte
b) a bit
c) 100 bits
d) none of above

3. Avalanche photo diode receivers can detect bits of transmitted data by receiving?
a) 100 photons
b) 200 photons
c) 2000 photons
d) 300 photons

4. Which of the following types of channels moves data relatively slowly?
a) wide band channel
b) voice band challen
c) narrow band channel
d) dialed service

5. Which of the following statement is incorrect?
a) The difference between synchronous and asynchronous transmission is the clocking derived from the data in synchronous transmission
b) Half duplex line is a communication line in which data can move in two directions, but not at the same time
c) Teleprocessing combines telecommunications and DP techniques in online activities
d) Batch processing is the prefered processing mode for telecommunication operation

6. Which of the following communication modes support two-way traffic but in only one direction at a time?
a) simplex
b) half duplex
c) three-quarters duplex
d) all of the above

7. How many OSI layers are covered in the X.25 standard?
a) Two
b) Three
c) Seven
d) Six

8. In OSI network architecture, the routing is performed by?
a) network layer
b) data link layer
c) transport layer
d) session layer

9. The transmission signal coding method of TI carrier is called?
a) Bipolar
b) NRZ
c) Manchester
d) Binary

10.Which of the following statement is incorrect?
a) Multiplexers are designed to accept data from several I/O devices and transmit a unified stream of data on one communication line
b) HDLC is a standard synchronous communication protocol.
c) RTS/CTS is the way the DTE indicates that it is ready to transmit data and the way the DCW indicates that it is ready to accept data
d) RTS/CTS is the way the terminal indicates ringing