Thales IoT Developer Community
Custom AT command for monitoring signal level
Showcase, June 14, 2019 - 3:16pm, 3197 views
New Java API available for ELS61 rel.2, PLS62 and EHSx rel.4 module allows to create custom AT commands. This showcase presents custom AT command that allows to monitor signal level. The same command can be used in all cellular technologies (2G, 3G, 4G).
To monitor signal level with standard AT commands, different command has to be used in 2G (AT+CSQ) and different in 3G/4G (AT^SMONI). Hence, only one custom AT command AT^CSQ makes monitoring signal easier.
Only exec mode of this command is available. In test mode and write mode it returns error.
If module is registered to the network it returns two lines. The first one is the description of parameters. Second line contains parameters themself:
-paramaters relevant for signal quality assessment (depending on used technology),
-unified rating in the scale from 1 to 5 (5 is the best signal).
^CSQ: Rat | RSSI [dBm] | Signal Bar [*/5]
^CSQ: 2G , -93 , 3
^CSQ: Rat | RSCP [dBm] | Ec/No [dB] | Signal Bar [*/5]
^CSQ: 3G , -57 , -9.0 , 5
^CSQ: Rat | RSRP [dBm] | RSRQ [dB] | Signal Bar [*/5]
^CSQ: 4G , -92 , -11.5 , 2
If module is not registered (or in airplane mode) it returns only "Not Registered".
^CSQ: Not Registered
After execution of AT^CSQ command, MIDlet sends command AT^SMONI to check registration state and cellular technology. If module is registered to the network, it reads relevant parameters (in 2G from AT+CSQ and in 3G/4G from AT^SMONI). Based on it, it assesses quality level and print it as a response together with other parameters.
In Logger.java, line 11, level of logs can be modified.