AT+QCSQ command conversion on EG21-G

IoT Modules LTE Standard Module
1

Hi, why is the lte_rssi parameter on this command for the EG21-G positive? With the BG96 I have this response:

AT+QCSQ
+QCSQ: "CAT-M1",-91,-129,67,-20

That makes sense to me but then I have this response with the EG21-G:

AT+QCSQ
+QCSQ: "LTE",77,-116,76,-17

Why is it 77 positive? Should I apply any conversion?
Thanks

2

Dear @Rafa_Hernandez ,

Thank you for reaching out.

On EG21-G, the LTE RSSI field in AT+QCSQ is reported as a positive magnitude (i.e., the absolute value), not as a signed dBm number. That’s why you see 77 instead of -77.

So you can interpret it like this for LTE on EG21-G:

LTE RSSI (dBm) = -lte_rssi when it is shown as a positive value
Example: 77 → -77 dBm

The other LTE values in the same line are already in their normal signed form and should be used as-is:

RSRP: -116 dBm

SINR: 76

RSRQ: -17 dB

So yes, for your EG21-G output, just treat the first LTE number as -77 dBm; no other conversion is needed.

Best Regards,
Aghelan

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4

@aghelan_loga thanks for your reply. Regarding the same command for the sinr parameter the BG96 documentation said this:
Logarithmic value of SINR. Values are in 1/5th of a dB. The range is 0–250 which translates to -20dB – +30dB
What does this mean and how can I do de conversion?
thanks

5

Dear @Rafa_Hernandez ,

Thank you for reaching out again.

That description means the SINR value returned by AT+QCSQ is not directly in dB. It’s an encoded number with two parts:

  1. Resolution: each step is 1/5 dB (0.2 dB)
  2. Offset: the scale starts at −20 dB

So the conversion to real SINR in dB is:

SINR(dB) = (sinr_value / 5) − 20

Example:

  • sinr_value = 0 → (0/5) − 20 = −20 dB
  • sinr_value = 250 → (250/5) − 20 = +30 dB
  • Your earlier CAT-M1 example: sinr_value = 67 → (67/5) − 20 = 13.4 − 20 = −6.6 dB

In code, just compute sinr_db = sinr_value * 0.2 - 20.

If you ever see a value outside the documented range (or a special “invalid” placeholder), treat it as “not available” rather than converting it.

Best Regards,
Aghelan

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