Typical simulator applications include testing the operation, performance and reliability of multiplexers, bridges, encrypters, network applications and other communications hardware and software. When used for link simulation, these simulators physically connect directly between two pieces of equipment to replace conventional data links such as satellite connections, WANs or telephone networks. They can also be used in line with a real data link to add additional delays or errors or to simulate the effects of adding an additional link to the system. The front panel has an eight line by 40-character display panel and 28 keys for entering parameters and operating the unit. Requires at least one interface module.