[General Questions and Answers] draqlek:
It is my first post here, so forgive me any mistakes. I'm a newbie to Android.

I've been drifting throughout the Internet and XDA-developers forum to find a solution to my problem, but I can't find it. You are my only hope. Even original support can't help. I bought a non-branded Android device for my car in April 2014, specifically this one: (happyshoppinglife[.com] / honda-civic-android-autoradio-dvd-navigation-with-dtv-wifi-3g-p-1168[.html]). Since then I can't connect to the Internet using 3G modem.

It seems to have some tailor-made Android version, since normal tablets don't have a DVD or FM radio or wheel-buttons.

Recently the manufacturer/developer upgraded the Android to a version 4.4.2 (chinabatemon [.com] / cargpss / android-update-442.rar)

Precisely it is:

Model SNT-210

Android 4.4.2-0140516-sntb-HOMEMADE

Kernel 3.0101-gdaab9de-dirty

QDroid@DevServer #9

Build omnisntb-eng 4.4.2 KOT49H eng.QDroid.20140516.133512 test-keys

iGo 9.6.7.235654-Thin1.1

Manual: autoradiodvdgpstv [.com] / user-manual / car-dvd / android-car-dvd-player-cp1.pdf

Currently I have 3g modems: Huawei E220 (VID 12d1:1003, PID 12d1:1003), Huawei K3770 (VID 12d1:14d1, PID 12d1:14c9), ZTE MF626 (VID 19d2:2000, PID 19d2:0031), Huawei E230 (VID 12d1:1003, PID 12d1:1003)

Wifi works fine, but I need 3g..

[EDIT]

I have no root access:

1|u0_a10@SNT-210: / $

after doing "su":

u0_a10@SNT-210: / $

I'm probably unable to root the device because I cannot connect to it (I got a cable: USB type A - USB type A, but it didn't work: no response from Android device nor from my laptop). After clicking "Build number" once (in the "About CarDVD" menu) it shows "No need, you are already a developer", but there are no "developer options" in the Settings menu.

There is the app "3g reconnect" already installed in the system, but after I connect a modem (E230, E220 or K3770) with working SIM (no PIN) in "Plus" (MCC 260 MNC 01) its LED is blinking green, and then blue after a while (one blink per 3-5 sec) but the system remains unchanged. The support (the Chinese via chat, not very nice experience talking: an hour waiting for response) said I .

I tried PPP Widget to help me, as well as Android Terminal and Slick USB 2 Serial Terminal.

I set PPP widget to start manually, set APN to "internet", left number to dial unchanged, no user, no password. After booting without 3g modem, PPP Widget starts and I connect the modem to a USB port. I click on the PPP icon, choose my E230 modem (12d1:1001) and I click connect. PPP Widget searches for the port and tries to connect.

When I turn on logging, portcheck.log says:

== START LOG ==

PPP Widget version 1.3.3

USB_ModeSwitch log from {date}

Raw args from udev: 1-1.1/portcheck

using top device dir /sys/bus/usb/device

SymLinkCheck called with /sys/bus/usb/ttyUSB0

My name is ttyUSB0

Checking my endpoints ...

in /sys/bus/usb/devices/1-1.1/1-1.1:1

checking ep_81 ...

ep_81 has interrupt transfer type

--> I am an interrupt port

--> No interrupt interface below me

{something was here}

== END LOG ==

When I check the Android Settings (Mobile status) there is:

Network: unknown

Signal strength: 2147483647 dBm 255 asu

Mobile network type: Unknown

Service state: Out of service

IMEI: {my SIM's IMEI}

IMEI SV: Unknown

IP address: Unavailable

WiFi MAC address: {some MAC address}

When I turn Android Terminal it goes:

lsusb:

Bus 001 Device 001: ID 1d6b:0002

Bus 002 Device 001: ID 1d6b:0001

Bus 001 Device 002: ID 05e3:0608

Bus 001 Device 003: ID 0bda:8176

Bus 001 Device 007: ID 12d1:1003

Bus 001 Device 005: ID 04e8:6860

Sometimes There is Bus 001 Device 005 instead of 007 by 12d1:1003

When I try to use Slick USB 2 Serial Terminal it connects to the modem and answers all the AT commands:

ATI

Huawei

E230

Rev. 11.104.20.00.00

IMEI...

+GCAP: +CGSM +DS +ES

AT+CSQ

15.99

AT^SYSINFO

2,3,0,5,1,,4

AT+COPS=?

(1,"Plus","PLUS","26001",0), (2,"Plus","PLUS","26001",2) ... {and other}

AT+COPS?

0,2,"26001",2

I can swich the modem's mode:

AT^U2DIAG=0

the default was AT^U2DIAG=257

After switching to AT^U2DIAG=0 the modem seems to be recognised by lsusb as 12d1:1001

I tried to connect manually:

AT+CGDCONT=1,"IP","internet"

ATD *99***1#

.. and it returned CONNECTED

but when I went back to the home screen and tried to check if there is Internet access (I turned on Chrome), there was no Internet access, but I have to revise this once more.