Using a Huawei E173 USB Modem for Calls (chan_dongle)

The Huawei E173 is a USB 3G modem from Huawei that is compatible with the chan_dongle module for Asterisk. By using this modem with chan_dongle, you can configure Asterisk to make voice calls and send SMS messages over the GSM network, effectively turning the modem into a full-fledged GSM gateway.

Preparing the USB Modem

1. First, let’s see which USB devices are connected to the PC:

lsusb
Bus 001 Device 002: ID 12d1:1001 Huawei Technologies Co., Ltd. E169/E620/E800 HSDPA Modem
Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
Bus 002 Device 003: ID 0e0f:0002 VMware, Inc. Virtual USB Hub
Bus 002 Device 002: ID 0e0f:0003 VMware, Inc. Virtual Mouse
Bus 002 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub

We’re interested in the device "12d1:1001 Huawei Technologies...".

• 12d1 – the vendor ID.

• 1001 – the product ID.

For the modem to function properly, you need to switch it to "1001" (modem-only mode).

1. Next, search for device info using the vendor ID "12d1":

dmesg | grep 12d1
[    2.828272] usb 1-1: New USB device found, idVendor=12d1, idProduct=1001, bcdDevice= 0.00

1. Then check for info by the USB device number "usb 1-1":

dmesg | grep 'usb 1-1'

[    2.262750] usb 1-1: new high-speed USB device number 2 using ehci-pci
[    2.828272] usb 1-1: New USB device found, idVendor=12d1, idProduct=1001, bcdDevice= 0.00
[    2.828479] usb 1-1: New USB device strings: Mfr=3, Product=2, SerialNumber=0
[    2.828641] usb 1-1: Product: HUAWEI Mobile
[    2.828754] usb 1-1: Manufacturer: HUAWEI Technology
[    2.856994] usb 1-1: GSM modem (1-port) converter now attached to ttyUSB0
[    2.861194] usb 1-1: GSM modem (1-port) converter now attached to ttyUSB1
[    2.864265] usb 1-1: GSM modem (1-port) converter now attached to ttyUSB2

We see the modem’s serial devices: ttyUSB0, ttyUSB1, ttyUSB2.

Checking the Modem Settings

minicom -D /dev/ttyUSB0

You’ll see something like:

Welcome to minicom 2.8

OPTIONS: I18n
Compiled on Apr 26 2021, 18:06:16.
Port /dev/ttyUSB0, 12:30:42

Press CTRL-A Z for help on special keys

You can now enter AT commands to manage and configure the modem.

Example Commands

• AT^CARDLOCK? – Checks SIM lock status and the remaining attempts to enter an unlock code. (The modem’s response: CARDLOCK: A,B,0. If A=2, modem is unlocked; A=1, locked — SimLock; A=3, you either used all 10 attempts or have a customized firmware. B is the remaining number of attempts, typically 10.)

• AT^CARDLOCK="NCK Code" – Unlock the modem to work with all mobile operators (if you have the code).

• AT^CVOICE=? – Checks the modem’s voice support state (0 means voice is enabled).

• AT^CVOICE=0 – Enables voice functions on the modem.

• AT^U2DIAG=0 – Switch the modem into modem-only mode.

What to Verify?

1. Confirm the modem supports voice functions.

2. The modem must be in "modem-only" mode (ID 1001).

3. If possible (and if you have a code), unlock the modem for use with any operator.

chan_dongle for Asterisk

1. In the MikoPBX web interface, go to System → Customize System Files.

2. Open /etc/asterisk/modules.conf.

3. Set the mode to "Append to the end of the file".

4. Add:

load => chan_dongle.so

1. Open /etc/asterisk/dongle.conf for editing.

2. Choose "Replace Completely".

3. Paste the following configuration:

[general]
interval=15

[defaults]
context=public-direct-dial
group=0
rxgain=0
txgain=0
autodeletesms=yes
resetdongle=yes
u2diag=-1
usecallingpres=yes
callingpres=allowed_passed_screen
disablesms=no

language=en
smsaspdu=yes
mindtmfgap=45
mindtmfduration=80
mindtmfinterval=200

callwaiting=auto
disable=no
initstate=start
dtmf=relax

[dongle0]
audio=/dev/ttyUSB1
data=/dev/ttyUSB2

1. Re-open /etc/asterisk/modules.conf.

2. Again choose "Append to the end of the file".

3. Add contexts for SMS and USSD handling:

[dongle-incoming-ussd]
exten => ussd,1,Noop(Incoming USSD: ${BASE64DECODE(${USSDBASE64})})
exten => ussd,n,Hangup()

[dongle-incoming-sms]
exten => sms,1,Noop(Incoming SMS from ${CALLERID(num)} ${BASE64_DECODE(${SMS_BASE64})})
exten => sms,n,Hangup()

1. After configuring dongle.conf, you must restart your PBX.

Configuring DID

Each dongle requires a DID number for correct inbound call handling.

1. Enter the Asterisk console:

asterisk -r

1. List the dongle devices:

mikopbx*CLI> dongle show devices
ID      Group State RSSI Model Firmware         IMEI IMSI Number
dongle0 0     Free  12   E173  11.126.15.00.209 ***  ***  79255283744

1. If the Number column is empty, run:

dongle cmd dongle0 AT+CPBS="ON"
dongle cmd dongle0 AT+CPBW=1,"79255283744",145

Restart your PBX afterwards.

Configuring an Inbound Route

1. In the web interface, go to Call Routing → Incoming Routing.

1. Create a new rule. In the DID field, specify the SIM’s phone number you set earlier:

Configuring Outbound Routes

1. In Call Routing → Providers, create a new SIP account with:

   • Name – “Dongle0” (or any name)

   • Host or IP – 127.0.0.1

   • Account Type – “Authentication by IP address, no password”

1. Copy the Provider ID from the browser address bar (e.g., SIP-TRUNK-C4153448).

1. In Call Routing → Outbound Routing, create a new rule for sending calls via the modem:

1. Go to System → System file customization and open /etc/asterisk/extensions.conf. Choose “Add to end of file” and add:

[SIP-TRUNK-C4153448-outgoing-custom]
exten => _[0-9*#+]!,1,Set(DIAL_COMMAND=Dongle/dongle0/${number})
 same => n,return