Mobile signal strength check

This page provides detailed information how to check mobile signal reception quality from command line. For general information on mobile networks and modems, please go to Mobile network - 3G/4G modem installation and configuration.

Note: This link shows a good description of what signal quality is needed: [1]

Standard method

In 2021 the software in most of the camera systems was upgraded to provide relatively user friendly mobile signal check functions.

Web GUI

click on tab "Network" then "Check modem signal"

Commandline

 dfn_print_mobile_signal_quality.sh

Critical details of the printed info explained

Both these print the same information - the Web GUI menu command just calls the script. The printed information depends on the type of modem installed in the camera system. The key things are:

There actually is a modem module, it is powered, and the host operating system can detect it on the USB bus: This is the 3G modem module:

 Detecting modem type...
 Bus 001 Device 042: ID 1199:68a3 Sierra Wireless, Inc. MC8700 Modem

This is the 4G modem module (Americas/EU version):

 Detecting modem type...
 Bus 001 Device 012: ID 1199:9071 Sierra Wireless, Inc. 

Modem missing or defunct:

 Detecting modem type...
 Error: no supported Sierra Wireless modem found.
 Modem missing? Or broken? Wiring problem? Here is a list of devices on USB:

It is possible to send AT commands to configure/query the modem, and it responds (3G+ modem module):

 Manufacturer: Sierra Wireless, Incorporated
 Model: MC8705

This is the 4G modem module (Americas/EMEA version):

 Manufacturer: Sierra Wireless, Incorporated
 Model: MC7455

Modem hardware and firmware version

  Revision: XXXXXXXXX YYYY XXXXXXXXX

Temperature reading! (In Celsius degrees, sensor in the modem module)

 Temperature: 40

Connection and registration state - this means whether the modem is attached/registered to the operator's network

All good:

 PS state:    Attached
 GMM (PS) state:REGISTERED       NORMAL SERVICE 
 MM (CS) state: IDLE             NORMAL SERVICE 

Not good - in this case, missing SIM card:

 PS state:    Not attached
 GMM (PS) state:DEREGISTERED     PLMN SEARCH    
 MM (CS) state: IDLE             NO IMSI        

Mobile technology, band and channel used to connect with the tower

3G/WCDMA - example:

 System mode:   WCDMA
 WCDMA band:    WCDMA800
 WCDMA channel: XXXX

4G/LTE - example:

 LTE band:      B2               LTE bw:      20 MHz  
 LTE Rx chan:   XXX              LTE Tx chan: XXXXX

Signal reception quality:

Note: This link shows a good description of what signal quality is needed: [2]

3G/WCDMA:

 RX level (dBm):-85

4G/LTS:

 PCC RxM RSSI:  -75              RSRP (dBm):  -112
 RSRQ (dB):     -19.0 
 ...
 LTE:
       RSSI: '-73 dBm'
       RSRQ: '-16 dB'
       RSRP: '-113 dBm'
       SNR: '0.0 dB'

Simple signal quality print - should be at least 5-6 in remote areas, > ~12-15 with busy tower:

 AT+CSQ
 +CSQ: 12,99

Lowest possible signal

 AT+CSQ
 +CSQ: 0,99

No signal

 AT+CSQ
 +CSQ: 99,99

Missing SIM card

 AT+CSQ
 ERROR

Mobile network operator - examples:

 +COPS: 0,0,"Telstra Mobile",2

or

 +COPS: 0,0,"OMANTEL",2

or

 +COPS: 0,0,"TELUS",7

missing SIM card or missing antenna or no reception

 +COPS: 0,0,"Limited Service",2

Low level commands for advanced users

4G (MC74xx) modem modules

Login to the camera system locally or remotely, in text console run the following commands.

Verbose signal reception print - 4G/LTE connection, good signal quality:

 root@XXXXXX:~# qmicli -d /dev/cdc-wdm1 --nas-get-signal-strength
 [/dev/cdc-wdm1] Successfully got signal strength
 Current:
       Network 'lte': '-68 dBm'
 RSSI:
       Network 'lte': '-68 dBm'
 ECIO:
       Network 'lte': '-2.5 dBm'
 IO: '-106 dBm'
 SINR: (8) '9.0 dB'
 RSRQ:
       Network 'lte': '-12 dB'
 SNR:
       Network 'lte': '1.0 dB'
 RSRP:
       Network 'lte': '-104 dBm'

Brief signal reception print - 4G/LTE connection, good signal quality:

 root@XXXXXX:~# qmicli -d /dev/cdc-wdm1 --nas-get-signal-info
 [/dev/cdc-wdm1] Successfully got signal info
 LTE:
       RSSI: '-68 dBm'
       RSRQ: '-12 dB'
       RSRP: '-104 dBm'
       SNR: '-4.4 dB'

Brief signal reception print - 4G/LTE connection, excellent signal quality:

 root@XXXXXX:~# qmicli -d /dev/cdc-wdm1 --nas-get-signal-info
 [/dev/cdc-wdm1] Successfully got signal info
 LTE:
       RSSI: '-62 dBm'
       RSRQ: '-7 dB'
       RSRP: '-90 dBm'
       SNR: '23.8 dB'

Brief signal reception print - 3G/WCDMA connection, marginal signal strength, but still good signal quality thanks to low noise/interference; typical for remote areas with low population:

 root@DFNEXT043:~# qmicli -d /dev/cdc-wdm1 --nas-get-signal-info
 [/dev/cdc-wdm1] Successfully got signal info
 WCDMA:
       RSSI: '-103 dBm'
       ECIO: '-6.5 dBm'

Verbose signal reception print - 3G/WCDMA connection, marginal signal strength, but still good signal quality thanks to low noise/interference; typical for remote areas with low population:

 root@DFNEXT043:~# qmicli -d /dev/cdc-wdm1 --nas-get-signal-strength
 [/dev/cdc-wdm1] Successfully got signal strength
 Current:
       Network 'umts': '-103 dBm'
 RSSI:
       Network 'umts': '-103 dBm'
 ECIO:
       Network 'umts': '-7.5 dBm'
 IO: '-106 dBm'
 SINR: (8) '9.0 dB'

Note: if device /dev/cdc-wdm1 was not working, try substitute 1 with 0 or 2. List devices available in your system with 'ls -l /dev/cdc-wdm*'.

 ls -l /dev/cdc-wdm*
 crw------- 1 root root 180, 0 Nov 26 11:53 /dev/cdc-wdm0
 crw------- 1 root root 180, 1 Nov 26 11:53 /dev/cdc-wdm1

3G modem modules (MC8705)

Login to the camera system, in text console run command 'minicom'. It should be preset to use the correct virtual serial port /dev/ttyS3. If not, run 'minicom -s' and select this port.

(To exit minicom, press 'Ctrl+a q'.)

Type following AT modem commands:

 at+csq
 +CSQ: 14,99
 
 OK
 at!gstatus?
 !GSTATUS: 
 Current Time:  7833862          Temperature: 61
 Bootup Time:   6442483          Mode:        ONLINE         
 System mode:   WCDMA            PS state:    Attached     
 WCDMA band:    WCDMA800         GSM band:    Unknown    
 WCDMA channel: 4436             GSM channel: 65535
 GMM (PS) state:REGISTERED       NORMAL SERVICE 
 MM (CS) state: IDLE             NORMAL SERVICE 
 
 WCDMA L1 State:L1M_DCH          RRC State:   CELL_DCH       
 RX level (dBm):-85
   
 OK

Signal strength (CSQ) >=5 is acceptable, although in country areas the internet may work even with lower signal quality as the masts are not too busy. In any case, the more the better. More than ~ 10 is usually very reliable connection in the remote areas. In urban areas with busy mobile network, better signal quality is required for reliable connection and data transfers - other devices connected to the same telco tower might "shout down" the communication of the camera system.