(66)is a one-way function that takes an arbitrarily long piece of plaintext and from it computes a fixed,length bit string.(67)is a protocol that most USENET machines now use it to allow news articles to propagate from one machine to another over a reliable connection.(68)is an approach preferred by cable TV providers. In this solution the fiber terminates at an opt~electrical converter and the final segment is a shared coaxial cable.(69)is a device used to connect two separate network that use different communication protocol.(70)is a digital-to-digital polar encoding method in which the signal level is always either positive or negative.