Yes. SH-055SDV is a high sensitive detector, it surely can detect RF (radio frequency) signal during 50 MHz ~ 6.0 GHz.
The LEDs lighting up indicates that there is wireless device operating around. No beep or no vibration menas that the signal is not GSM signal
No. SH-055SDV does not need special operation method, just different definitionn on the warning.
SH-055SDV will verify received signal is GSM signal or not. If it is GSM signal, the detector will beep or vibrate to notify the user. If it is other wireless signal, the detector will beep in silent.