ELECTRONIC COMMUNICATION EQUIPMENT, NAMELY, HIGH SPEED DIGITAL TEST AND MEASUREMENT APPARATUS IN THE NATURE OF; GENERATORS AND TRANSMITTERS FOR PRODUCING PSEUDORANDOM AND PROGRAMMABLE DIGITAL DATA PATTERNS; RECEIVERS AND ANALYZERS FOR DISSECTING, IDENTIFYING, CHANGING, AND MEASURING DIGITAL TRANSMISSION PROTOCOLS, PATTERNS, AND WAVEFORMS; AND BIT ERROR TEST UNITS FOR DETECTING, RECORDING AND ANALYZING DIGITAL TRANSMISSION ERRORS