27) If a network designer wants to connect 5 routers as point-to-point simplex line, then total number of lines required would be

28) To interface a computer terminal with a modem, required physical layer standard is

29) A 100 km long cable runs at the T1 data rate. The propagation speed in the cable is half the speed of light. How many bits is in the cable

30) How much bandwidth is there in 0.1 micron of spectrum at a wavelength of 1 micron ?

31) It is desired to send a sequence of computer screen images over an optical fiber. The screen is 480 x 640 pixels, each pixel being 24 bits. There are 60 screen images per second. How much bandwidth is needed, and how many microns of wavelenth are needed for this band at 1.30 microns