PCIe B Key

The following is the procedure of Radxa CM3I IO Board using the Mobile LTE EM05-CE module.

Quectel LTE EM05-CE Physical Image

• The 4G module demonstrated here is: Quectel EM05-CE

  

Connecting Peripherals

First of all, you need to plug the Quectel LTE EM05-CE into the B-key connector of Radxa CM3I IO Board and insert the SIM card.

• The installation position is as shown in the figure:

  

• The SIM card slot location and insertion direction is shown in the figure:

  

You can check if the device is connected with the following command:

radxa@radxa-cm3i-io:~$ lsusb | grep -i Quectel Bus 002 Device 002: ID
2c7c:0125 Quectel Wireless Solutions Co. EC25 LTE modem

The modem usually communicates with the host via the serial port. Please check that the system enumerates the corresponding serial devices correctly:

radxa@radxa-cm3i-io:~$ ls /dev/ttyUSB*
/dev/ttyUSB0  /dev/ttyUSB1  /dev/ttyUSB2  /dev/ttyUSB3

Installing related software

Execute the following commands in the terminal to install dial-up related software:

sudo apt update
sudo apt install ppp picocom net-tools

Testing the modem with the at command

First, open the serial port with picocom:

sudo picocom -b 115200 /dev/ttyUSB3

After the programme has started, the modem status can be checked by entering the following at command:

at+cpin?
+CPIN: READY

OK  #Check if the SIM card is in place

at+csq
+CSQ: 31,99

OK  #Detects signal, 99 means no signal.

at+cops?
+COPS: 1,0,"CHN-UNICOM",7

OK  #View Operator

at+creg?
+CREG: 0,1

OK  #Get the registration status of the mobile phone (0,1: indicates that the registration is normal)

at+qeng="servingcell"
+QENG: "servingcell","NOCONN","LTE","FDD",460,01,19A358C,366,100,1,5,5,774E,-108,-5,-83,9,13

OK  #Displays the signal strength and quality of the currently connected service cell

If the modems all return to normal, use the Ctrl+A Ctrl+X key combination to exit picocom.

Dial-up via `ppp'

In a terminal, execute the following command to switch to the peers directory and add the ppp dial-up configuration script.

sudo su
cd /etc/ppp/peers

Use the vi editor to add the first script file, rasppp, which looks like this:

# Hide password when connecting for debugging
hide-password

# Don't need authentication for this phone
noauth

# For call control scripts
connect '/usr/sbin/chat -s -v -f /etc/ppp/peers/rasppp-chat-connect'

# for disconnect scripts
disconnect '/usr/sbin/chat -s -v -f /etc/ppp/peers/rasppp-chat-disconnect'

# Debugging information
debug

# 4G module
/dev/ttyUSB3

# Serial baud rate
115200

# Use default route
defaultroute

# Do not use default IP
noipdefault

# do not use PPP compression
novj
novjccomp
noccp
ipcp-accept-local
ipcp-accept-remote
local

# It is best to lock the serial bus by creating a lock file so that other programs will know that the corresponding serial port is already in use once they discover the existence of this file.
lock
dump

nodetach

# username password (configuration varies by operator)
user [email protected]
password vnet.mobi

# hardware control flow
crtscts
remotename 3gppp
ipparam 3gppp

# Set the usepeerdns parameter if you want to use the DNS negotiated on the server side.
usepeerdns

Add a second script, rasppp-chat-connect, which looks like this:

TIMEOUT 15
ABORT "BUSY"
ABORT "ERROR"
ABORT "NO ANSWER"
ABORT "NO CARRTER"
ABORT "NO DIALTONE"

""AT
OK \rATZ

ok \rAT+CGDCONT=1, "ip",""

ok-at-ok atdt#777
CONNECT \d\c

Add a third script file rasppp-chat-disconnect with the following script:

ABORT "ERROR"
ABORT "NO DIALTONE"
SAY "\NSending break to the modem\n"

""\k""

""+++ATH""
SAY "\nGood bye ! \n"

After adding the above three script files, you can now try dialling using ppp:

sudo pppd call rasppp & # dialling in the background

The complete dialling process is shown in the image.

From the output of the program we can get the following information:

1. local IP address: `10.5.65.99
2. Primary DNS server: 202.96.128.86 3. Secondary DNS server: 10.5.65.99 4.
3. Secondary DNS server: 202.96.134.133.

We can now configure the network based on the above information:

sudo ip route add default via 10.224.236.90 # configure the gateway
echo "nameserver 120.80.80.80" | sudo tee -a /etc/resolv.conf # configure primary DNS
echo "nameserver 221.5.88.88" | sudo tee -a /etc/resolv.conf # Configure secondary DNS

You can now use the ping command to check if you are connected to the Internet:

Troubleshooting

1. My system does not list USB serial devices.

Please check if the corresponding driver is included in your current running system. You can run the following command to check:

radxa@rock-3b:~$ lsmod | grep usb
usb_wwan 20480 1 option
usbserial 36864 2 usb_wwan,option