otdr 1310nm/1550nm ,850nm/1310nm/1550nm, 1310nm/1550nm/1490nm 13/15dB 22/23dB 32/30dB 36/35dB 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 ...