Specialized measurement equipment category for diagnosing, monitoring, and analyzing network communication quality in manufacturing environments. Includes industrial Ethernet-compatible network analyzers, cable testers, protocol analyzers, packet capture devices, communication quality meters, LAN testers, and optical fiber measurement instruments. Used for FA equipment communication fault diagnosis, network performance evaluation, security auditing, and communication protocol analysis. Targets high-performance measurement instruments with detailed communication data analysis and quality evaluation capabilities, not simple connection verification devices. Industrial-grade specialized measurement equipment that supports preventive maintenance to prevent manufacturing line shutdowns and rapid root cause identification during failures.