Received signal strength indicator

RSSI is a initialism for Received Signal Strength Indication

RSSI is measurement of the strength (not necessarily quality) of the received signal strength in a WiFi networking or Bluetooth adapter, in arbitrary units. RSSI is used internally in a wireless networking card to determine when the signal is below a certain threshold at which point the network card is clear to send (CTS). Once the card is clear to send, a packet of information can be sent. The End-user will likely observe a RSSI value when measuring the signal strength of a wireless network through the use of a wireless network monitoring tool like Network Stumbler.

RSSI measurements will vary from 0 to 255 depending on the vender. A value of 1 will indicate the minimum signal strength detectable by the wireless card, while 0 indicates no signal. The value has a maximum of RSSI_Max. For example, Cisco Systems cards will return a RSSI of 0 to 101. In this case, the RSSI_Max is 101. The Cisco card can report 101 distinct power levels.

See converting RSSI values to other signal strength indicators: Converting_Signal_Strength.pdf