#!/bin/bash
modem=/dev/ttyUSB3
file=/home/giuseppe/Desktop/SCRIPTMODEM/imsi.txt

# print error to stderr and exit unsuccessfully
die() {
    echo "$@" >&2
    exit 1
}

# chat helper. try everything twice.
send_expect() {
    chat -v -f 'ABORT ERROR' '' "$@" '' || chat -v -f 'ABORT ERROR' '' "$@" ''
}

# keep modem open, so CD doesn't go low and drop connection
# move terminal to FD3 to avoid redirects on everything else ...
exec 3<&1 >"$modem" <"$modem"

# setup modem options ...
stty 115200

if ! [ -e "$modem" ]; then
    die 'Modem not connected'
fi

if ! send_expect 'AT+CREG?' '+CREG: 0,1'; then
    die 'Modem not registered'
fi

if ! send_expect 'AT!PADSETUP=1,2,82.91.28.127,0,9940,0,1' 'OK'; then
    die 'M2M connection failed'
fi

if ! send_expect 'AT+CGDCONT=1,"IP","web.omnitel.it"' 'OK'; then
    die 'APN setup failed'
fi

if ! send_expect 'AT!PADCONN=1' 'CONNECT'; then
    die 'Unable to open socket'
fi

cat "$file"

# give user idea of success
echo "done" >&3

[ -e "$modem" ] || die 'Modem not connected'
send_expect 'AT+CREG?' '+CREG: 0,1' || die 'Modem not registered'
send_expect 'AT!PADSETUP=1,2,82.91.28.127,0,9940,0,1' 'OK' || die 'M2M connection failed'
send_expect 'AT+CGDCONT=1,"IP","web.omnitel.it"' 'OK' || die 'APN setup failed'
send_expect 'AT!PADCONN=1' 'CONNECT' || die 'Unable to open socket'