6. It is desired to send a sequence of computer screen images over an optical fiber. The screen is 25601600 pixels, each pixel being 24 bits. There are 60 screen images per second. How much bandwidth is needed, and how many microns of wavelength are needed for this band at 1.30 microns? (10p) 7. Consider a code with only four valid codewords: 0000000000,0000011111,1111100000, 1111111111. (10p) a) What is the Hamming Distance in this given code? b) Prove your answer? c) What is the lower limit on the check bits for this code to correct single errors? 8. The following character encoding is used in a data link protocol: (15p) A: 01000111 B: 11100011 FLAG: 01111110 ESC: 11100000 a) Show the bit sequence transmitted (in binary) for the four-character frame A B ESC FLAG when each of the following framing methods is used: I. Byte count. II. Flag bytes with byte stuffing. III. Starting and ending flag bytes with bit stuffing. 9. Provide the definitions and examples for the following data-link terms: (15p) a) unacknowledged connectionless service, b) acknowledged connectionless service, c) acknowledged connection-oriented service, d) Error control, e) Error detection, f) Error correction