his entails either the use of more costly high-speed lines, or a longer transmission time. Tone trans- mission also requires terminal resolution capabilities of 200 lines per inch or higher. 4.5 INTEGRATED WORKSTATIONS Integrated workstations are keyboard/display devices that permit the creation of integrated text and graphic material on the display screen for eventual printout or communication with another system. These workstations are usually self-contained, and have dedicated files and simplified programming via symbolic keys and menu or symbol se- lection from the screen. The display can present characters in several sizes and in different type fonts, and the screen usually may be split into two or more individually controllable work areas. The keyboard is a conventional typewriter keyboard, but there usually are auxiliary keyboards and other devices that can be used to add data or move it on the display screen, such as a light pen, track ball, or "mouse." Externally, the workstation may look like a conventional CRT, but the capabilities are much greater. NETWORK MANAGEMENT 5.1 NETWORK CONTROL DESIGN CONSIDERATIONS Many existing network control facilities have been constructed in a piecemeal fashion, often for obvious financial reasons, but also due to application growth at new locations and availability of new equip- ment. While this fragmented situation is less desirable than designing an entire network control system at the onset, it certainly is not hope- less. Naturally, the kind of network control equipment required will be dictated to a great extent by the number of lines you have and plan to have. If you have only a few lines then it is difficult to justify expensive automatic monitoring, testing and switching devices. On the other hand, if you have a few hundred lines then it will cost you more not to have this kind of equipment. One underlying consideration which plays over all others is: How much are your data worth? Or, how long can you afford for a line or group of lines to be down? If your netw