axis of a robot arm function as? 20. List four types of communication tasks provided by local area networks. 21. Name three common types of transmission media. 22. What are the three general levels of functionality of industrial networks? 23. Define the term node as it applies to a network. 24. Explain the physical layout of devices on a network for each of the following network topologies: a. Star b. Bus 25. Compare device and process bus networks. 26. Define the term protocol as it applies to a network. 27. What is the function of a network gateway? 28. Define the term access method as it applies to a network. 29. Summarize the token passing network access method. 30. Summarize the collision detection network access method. 31. Summarize the polling network access method. 32. Compare parallel and serial data transmission. 33. Compare half-duplex and full-duplex data transmission. 34. Explain how networking schemes minimize the amount of wiring required. 35. What type of access control is used with DH+? 36. Compare the transmitting distances of RS-232 and RS-422/485 serial types. 37. What is DeviceNet used for? 38. List three pieces of information obtained from DeviceNet devices by the network scanner. 39. What is ControlNet used for?