at+CSQ, RSSI value and RSSI bar

at+CSQ

What do the numbers mean?

The number returned by the AT+CSQ command gives you a more accurate measurement of signal strength. The following table lists the dBm equivalent measurements (note that the dBm measurements are negative, so a higher negative number represents a lower signal strength):

0 < -113 dBm (Marginal) 1 -111 dBm (Marginal) 2 -109 dBm (Marginal) 3 -107 dBm (Marginal) 4 -105 dBm (Marginal) 5 -103 dBm (Marginal) 6 -101 dBm (Marginal) 7 -99 dBm (Marginal) 8 -97 dBm (Marginal) 9 -95 dBm (Marginal) 10 -93 dBm (Workable under most conditions) 11 -91 dBm (Workable under most conditions) 12 -89 dBm (Workable under most conditions) 13 -87 dBm (Workable under most conditions) 14 -85 dBm (Workable under most conditions) 15 -83 dBm (Good) 16 -81 dBm (Good) 17 -79 dBm (Good) 18 -77 dBm (Good) 19 -75 dBm (Good) 20 -73 dBm (Excellent) 21 -71 dBm (Excellent) 22 -69 dBm (Excellent) 23 -67 dBm (Excellent) 24 -65 dBm (Excellent) 25 -63 dBm (Excellent) 26 -61 dBm (Excellent) 27 -59 dBm (Excellent) 28 -57 dBm (Excellent) 29 -55 dBm (Excellent) 30 -53 dBm (Excellent) 31 > -51 dBm (Excellent)

So what do these numbers mean?

• Marginal – Levels of -95dBm or lower. At these sort of levels, it is very likely that you may suffer low throughput and disconnects due to cell loading/breathing even with an outdoor antenna.
• Workable under most conditions – Levels of -85dBm to -95dBm – Probably worth considering an outdoor gain type antenna. Could suffer poor throughput and disconnects due to cell loading/breathing.
• Good – Levels between -75dBm and -85dBm – normally no problem holding a connection with this sort of level (even with cell breathing) without the use of an external antenna.
• Excellent – levels above -75dBm. Should not be affected by cell breathing/loading and should not require an external antenna.

For those who are technically oriented, as most BB Users are, and want MORE, here is an approximate tabulation of the # of Bars vs. signal level in dBM:
1 bar ~ -102 to -120 dBM
2 Bars ~ -93 to -101 dBM
3 Bars ~ -87 to -92 dBM
4 Bars ~ -78 to -86 dBM
5 Bars ~ -40 to -77 dBM

Signal Bar Strength Indicators	RSSI Indicators
5 bars (optimal strength)	-77 or higher
4 bars	-78 to 86
3 bars	-87 to -92
2 bars	-93 to -101
1 bar	-102 or lower