Plain-language answer: RSSI is a receiver’s indication of received signal strength, usually an internal relative or calibrated value.
Why the definition matters
Its scale, bandwidth, averaging, and calibration vary by device; an RSSI number from one radio may not match another radio or equal dBm.
Use the number correctly
Use the manufacturer’s definition and compare readings on the same device with unchanged settings when making relative tests.
The common mistake
Treating an undocumented RSSI value as laboratory-calibrated field strength.
Measurement and safety boundary
Keep reference units, bandwidth, detector, direction, averaging, and test conditions attached to every number. Current regulator requirements and the complete installed system control RF-exposure compliance.
