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Posted: 17 Aug 2011, 22:17
by kennylam
DefaultVendor= 0x19d2

TargetVendor= 0x19d2


Extra AT command for locking the device to use only 4G LTE , have fun!!
The above setting has been tested on ZTE MF820 (CSL Hong Kong Ver.) with one2free SIM card only.

Posted: 18 Aug 2011, 19:11
by Josh
Thank you very much!

Especially for the AT command which may prove very useful. I quote from your posting on HKEPC if you don't mind:

Code: Select all

AT+ZSNT=0,0,0 (Auto) - Default
AT+ZSNT=1,0,0 GPRS Only
AT+ZSNT=2,0,0 3G Only
AT+ZSNT=0,0,1 GPRS Preferred
AT+ZSNT=0,0,2 3G Preferred

AT+ZSNT=6,0,0 LTE Only (Tested)
AT+ZSNT=0,0,6 LTE Preferred (Not tested yet)
May I add your name as the contributor of this device in the coming versions of the device reference?

Posted: 20 Aug 2011, 22:26
by kennylam

In addition
1) CheckSuccess=20 should be added to the config as well. It is tested work.
2) I tested that the usbserial module in kernel 2.6.38 works on ZTE MF820 with "modprobe usbserial product=0x19d2 vendor=0x0167". However, Kernel 2.6.35 doesn't not work even with forced product/vendor ID.

Posted: 22 Aug 2011, 19:59
by Josh
In any case, the driver "option" is recommended for high speed modems.

If it does not know the USB ID of the modem yet, it can be activated manually:

Code: Select all

# modprobe -v option
# echo "19d2 0167" > /sys/bus/usb-serial/drivers/option1/new_id

Posted: 23 Aug 2011, 21:15
by kennylam
I have tested that the driver "option" results lesser CPU usage on a OpenWRT powered router. However, the driver "usb-serial" result better transfer speed when using single TCP connection.

Testing setup: maximum downstream only, value taken from DUmeter, TP-Link WR841NDv3 with USB 2.0 mod

Downloading using FlashGet with 10 connections:
usb-serial: 3.2MB/s,CPU 75%
option: 3.2MB/s,CPU 96%

OFTA Hong Kong:
usb-serial: 2.9MB/s,Latency 30ms,Jitter 4ms
option: 2.5MB/s,Latency 29ms,Jitter 1ms

Posted: 24 Aug 2011, 10:51
by kennylam
oops, the CPU usage was just swapped, the correct value should be as follow:

usb-serial: 3.2MB/s,CPU 96%
option: 3.2MB/s,CPU 75%

the driver "option" takes much lesser CPU time