Signal Quality
With Online AT Command Tester tool, you can get the signal level of the device. The response for the AT+CSQ comamnd is also interpreted for teh corresponding dBm value.
To find out what signal qualities are supported,
AT+CSQ=?
+CSQ: (0-31,99),(0-7,99)
OK
The first part of the response is RSSI (Received signal strength indicator) and the possible values are,
0 -113 dBm or less
1 -111 dBm
2…30 -109… -53 dBm
31 -51 dBm or greater
99 not known or not detectable
The second part of the response is the Bit Error Rate (BER) and the possible values are,
0…7 as RXQUAL values in the table in 3GPP TS 45.008 [20] subclause 8.2.4
99 not known or not detectable
Now to get the signal level,
AT+CSQ
+Csq: 25,99
OK
The RSSI values returned by the CSQ command is mapped to dBm value in the table below. In the above example, rssi value of 25 corresponds to -63 dBm which implies an excellent signal condition.
| Value | RSSI dBm | Condition |
| 2 | -109 | Marginal |
| 3 | -107 | Marginal |
| 4 | -105 | Marginal |
| 5 | -103 | Marginal |
| 6 | -101 | Marginal |
| 7 | -99 | Marginal |
| 8 | -97 | Marginal |
| 9 | -95 | Marginal |
| 10 | -93 | OK |
| 11 | -91 | OK |
| 12 | -89 | OK |
| 13 | -87 | OK |
| 14 | -85 | OK |
| 15 | -83 | Good |
| 16 | -81 | Good |
| 17 | -79 | Good |
| 18 | -77 | Good |
| 19 | -75 | Good |
| 20 | -73 | Excellent |
| 21 | -71 | Excellent |
| 22 | -69 | Excellent |
| 23 | -67 | Excellent |
| 24 | -65 | Excellent |
| 25 | -63 | Excellent |
| 26 | -61 | Excellent |
| 27 | -59 | Excellent |
| 28 | -57 | Excellent |
| 29 | -55 | Excellent |
| 30 | -53 | Excellent |