31. What is the minimum number of wires needed to send data over a serial communication link layer?
A. 1
B. 2
C. 4
D. 6
E. none of the above
32. The _____ layer is the layer closest to the transmission medium.
A. transport
B. network
C. data link
D. physical
E. None of the above
33. What is the name of the device that connects two computers by means of a telephone line?
A. Tape
B. modem
C. bus
D. cable
E. None of the above
34. What is the main difference between DDCMP and SDLG?
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
E. None of the above
35. On a class B network, how many subnets are available with a subnet mask of 248?
A. 2
B. 6
C. 30
D. 62
E. 126