Abstract: A system for diagnosing and controlling operation of a plurality of modems, some located at a central site and others at various remote sites. A processor located at the central site selectively addresses microprocessor test and control units at each modem over a secondary channel. The microprocessor test and control units respond to commands to configure and perform various modem tests, operate autonomously to monitor various alarm conditions, and format status reports and alarm maydays for transmission back to the central processor. The system is capable of performing a wide variety of testing, monitoring and network control functions for a very large network of modems.

Abstract: A data display communication system wherein data generated locally by a keyboard or generated remotely and communicated by modems is displayed on a display device. Data displayed on the screen can be edited or reformatted prior to storage, print-out, or transmission to a remote location. Data communicated between storage and the central processing unit is handled in blocks that make up one full line of characters on the display device. All edit and format functions are performed on the basis of these blocks of data. Timing for the display device controls the operation of the system. The communication system utilizes a microprocessor operating in conjunction with specific hardware logic to handle display oriented operations.