EC200T-CN Linux driver serial port unstable

I am using EC200T-CN module with ARM Linux using usbserial driver.
My kernel version is 3.4.104
Module VID:2c7c, PID:6026
I used provided driver 3.4.111 folder and compiled 3 module
option.ko usb_wwan.ko and qcserial.ko
option driver detect port and create 4 port /dev/tty-USB0-3
/dev/tty-USB0 and /dev/tty-USB1 don’t respond.
While /dev/tty-USB2 and /dev/tty-USB3 respond to at command.
But serial port is unstable sudelly give error and exit from serial console.
When make pppd connection chat get error and exit.
Get following error when port detected.
option_instat_callback: error -2

Please help.

Please refer to the attached document to check whether your port selection and driver migration are correct. If you still have problems, please paste the detailed log of your PPP dialing.
Quectel_EC200T_Linux_USB_Driver_User_Guide_V1.0.pdf (623.0 KB)