Here is a bash script to automate the process:

(remove backslash before square brackets)

#!/bin/bash
ATinterface="/dev/ttyACM0"
APN="uinternet"

exec <> $ATinterface

function send_command {
	ret=""
	echo -e "AT cmd:$1"
	echo -e "$1" > $ATinterface
	while read line < $ATinterface; do
		if \[\[ ${#line} != 1 \]\] ; then
			echo "      : $line"
			ret=$ret$line
		fi
		if \[\[ $line == *"OK"* \]\] ; then
			return 0
		fi
		if \[\[ $line == *"ERROR"* \]\] || \[\[ $line == *"NO CARRIER"* \]\]; then 
			return -1
		fi
	done

}

if [ -e "$ATinterface" ]
then
	echo "Using $ATinterface"
else
	echo "$ATinterface is not found, turn on the modem"
fi

send_command "\rATE0\r"         # Echo off
send_command "AT+CMEE=2\r"	# Verbose ERRORs
send_command "AT+CPIN?\r"	# SIM / PIN status
result=$?
if [ $result != 0 ] 
then 
	echo "ERROR: SIM / PIN problem"
	exit -1
fi
send_command "AT+COPS=2\r"    # De-register from network
send_command "AT+CGDCONT=3\r" # Reset PDP context 3
send_command "AT+CGDCONT=3,\"IP\",\"$APN\"\r" # Set APN 
#send_command "AT+COPS=0\r"   # Register Automatically
send_command "AT+COPS=1,1,\"Partner\",7\r" # Reg. Partner LTE
send_command "AT+COPS?\r"     # Check registration status
send_command "AT^SWWAN?\r"    # Check WAN network status 
send_command "AT^SWWAN=1,3\r" # Activate WAN network