FID-30R and FID-31R identify light power presence in optical fibers and include 3 detection functions: TONE, TRAFFIC, and ONU. While both battery-operated models include trigger-operated clamp, FID-30R also includes optical power meter. LCD touch panel lets user view estimated optical power in fiber and select desired wavelength of 1,310, 1,490, or 1,550 nm. Identification of modulated tones at 270 Hz, 1 kHz, and 2,kHz is provided along with continuous wave and ONU signals.