Since 12.00.005 is not certified for use in North America.
We have no choice but use 12.00.004 firmware for Telit HE910.
Unfortunately, with 12.00.004 firmware, AT#SERVINFO, AT#RFSTS, AT#MONI has problems reporting the signal strength when the cellular network is of type 3G. Verified in India with many 12.00.004 firmware running Telit HE910 devices. Looks 12.00.004 has real problems regarding that and fixed in 12.00.005. ID#17110 Improvement MONI output
reporting to avoid not valid data during a voice call ID#16875 Handling AT#RFSTS report during
So, we switched to AT+CSQ to get signal strength.
——————————————————————————————————————–Data : We read Telit_HE910_UE910_UL865_AT_Commands_Reference_Guide_r7.pdf and derived the following logic to get actual dBm from AT+CSQ output.
(CSQ_Output * 2) – 113Example : If CSQ output is 26. Signal Strength in dBm is (26 * 2) -113 = -61 dBm ./ -60 dBm
Question 1: Can the above logic be used for both 2G and 3G networks ? Because we are little confused as two different scaling mentioned for 3GPP TS25.133 and 3GPP TS27.007 in Telit AT document. I am assuming all these are internally taken care and AT+CSQ output can be used for both 2G and 3G network as in above logic. Is that correct ? If not, what would be the logic, to derive dBm from AT+CSQ output for 3G network ?
——————————————————————————————————————–Data : With 2G network, below response for AT command responses are found.
– Applying the logic for AT+CSQ Output ((15 * 2 ) -113) , we get -83 dBm as signal strength.
– Same time Same second, AT#SERVINFO reports -79 dBm.
– On multiple runs, we observed a difference of 4 – 6 dBm’s with respect to AT+CSQ and AT#SERVINFO.
– Network is 2G (Take a look at AT+COPS? output).
– Network doesn’t change in the process.
Question 2 : Incorrect AT#SERVINFO behavior for 2G Networks as well (in 12.00.004 firmare) ?
Question 3 : Can we have information for below AT commands on what would be the maximum time to wait before we look for data from the Telit HE910 ?
Earlier we assumed all the above commands takes a second or less to respond for Telit HE910. But, we observed AT#SERVINFO and AT$GPSP? at times takes more than a second, if we ran in loop continuously. Rather than programming our software to wait for a blind amount of delay, we would like to hear from you, what would be the maximum delay for each of the above AT Commands. ——————————————————————————————————————–Question 4 : Does response for above listed AT commands always contain either one of the two strings in it, "OK" or "ERROR" ?
Knowing this helps us to confirm that FULL response is received for the sent AT command in our software.
Telit Technical Team
Let me know if you are looking for any more, additional detail to answer the questions we have. I can help with that.
We have got answers for most of the questions from Telit America Technical Support Team
Answer for Question 1:
———–———–———–———–———–———–———–———–———–———–———–Answer for Question 2 :
regarding question nr.4 :
you should find the answers in 3.2. AT Command Syntax chapter of HE910 AT commands reference guide.
Regarding question nr.5:
this could happen because temporary fading can happen between one command issuing and the next one, caused by many factors if you are in a real enviornment, especially if with a network which most of the times has poor signal
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