RPi3 internet and receive calls

Hello forumers,

I am using RPi3 and I would like to use internet and receive calls at the same time.

I already tried that with USB modem HUAWEI E220 but there was no success. I also have HUAWEI E3531.

I just need internet connection to be running all the time and when I receive call I just get its number and cancel it without answering. When I get its number I need to check if it exists in database.

Do you know which USB modem / shield / modem should I use to perform this action?

----

I can read the number via AT commands, but I cannot use the internet connection at the same time because ports are busy.

import serial, re

command_channel = serial.Serial(
        port='/dev/ttyUSB0',
        baudrate=115200,
        parity=serial.PARITY_NONE,
        stopbits=serial.STOPBITS_ONE,
        bytesize=serial.EIGHTBITS
)

if(command_channel.isOpen() == False):
    command_channel.open()
else:
    print 'Port is already open'

#enable caller id
command_channel.write("AT+CLIP=1" + "\r\n")
# command_channel.close()

ser = serial.Serial(
        port='/dev/ttyUSB1',
        baudrate=9600,
        parity=serial.PARITY_NONE,
        stopbits=serial.STOPBITS_ONE,
        bytesize=serial.EIGHTBITS
)

if(ser.isOpen() == False):
    ser.open()
else:
    print 'Port is already open'

while 1:
        buffer = ser.read(ser.inWaiting()).strip()
        buffer = buffer.replace("\n","")
        
        if((str(buffer)).startswith('+CLIP')):  
            print(str(buffer)) # number


            if(command_channel.isOpen() == False):
                command_channel.open()
            else:
                print 'Port is already open'

            # cancel the call
            command_channel.write('AT+CVHU=0'+'\r\n')
            command_channel.write('ATH'+'\r\n')


            command_channel.close()

And I can connect to internet with VW dial using this config:

[Dialer defaults]
Phone = *99***1#
Username = username
Password = password
Stupid Mode = 1
Dial Command = ATDT

[Dialer hsdpa]
Modem = /dev/ttyUSB0
Baud = 460800
Init2 = ATZ
Init3 = ATQ0 V1 E1 S0=0 &C1 &D2 +FCLASS=0
ISDN = 0
Modem Type = Analog Modem

And the connection output:

pi@raspberrypi:~ $ sudo wvdial hsdpa
--> WvDial: Internet dialer version 1.61
--> Initializing modem.
--> Sending: ATZ
OK
--> Sending: ATZ
ATZ
OK
--> Sending: ATQ0 V1 E1 S0=0 &C1 &D2 +FCLASS=0
ATQ0 V1 E1 S0=0 &C1 &D2 +FCLASS=0
OK
--> Modem initialized.
--> Sending: ATDT*99***1#
--> Waiting for carrier.
ATDT*99***1#
CONNECT
--> Carrier detected.  Starting PPP immediately.
--> Starting pppd at Mon Feb  6 15:54:35 2017
--> Pid of pppd: 2206
--> Using interface ppp0
--> local  IP address 172.17.245.69
--> remote IP address 10.64.64.64
--> primary   DNS address 109.239.187.4
--> secondary DNS address 109.239.187.20

The problem is that I use ttyUSB0 to send AT command and ttyUSB1 to read the CLIP and RING messages, so I cannot use WVDIAL on these ports.

Should I buy a new modem or any other solution exists?

Thank you for your help

BR, Matevz