FIBER-OPTIC communications systems continue to soar in bandwidth and operating data rates. With the growth of high-speed information services brought by Synchronous Optical Network (SONET), synchronous-digital-hierarchy (SDH), asynchronous-transfer-mode (ATM), piesiochronous-digital-hierarchy (PDH), Fiber Distributed Data Interface (FDDI), and other fiber-optic-based protocol configurations, manufacturers of optical test equipment must try to stay one step ahead of the latest set of component and system-level requirements.