Digital Portable Palm OTDR Meter Tester RY-OT4000 32/30dB 1310nm/1550n Overview RUIYAN OTDR-4000 series portable optical time domain reflectometry (OTDR) is the latest FTTx optical fiber cable-based test instrument. It has light weight, elegant appearance, small size, easiness of installation and maintenance, high-capacity built-in battery. It provides multiple built-in test wavelengths and optical testing functions…