VeEX FX87 User Manual page 14

Selecting the channel for the DWDM LS mode
Tone Detection: Press |F3| repeatedly to set modulation frequency: 270 Hz, 330 Hz, 1000 Hz,
2000 Hz, AUTO, CW. AUTO cycles channels every 18-20 seconds.
FX87 DWDM Tunable Laser Source User's Manual
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