User's Manual

L811-EA Module Hardware User Manual Page
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1
High/Floating
For Android or Linux system, the module`s USB ports mapped as 3*ACM
ports.
2
Low
For Win8 or Win10 system, the module`s USB port is mapped as a MBIM
mode.
Description:
1. During booting, the implementation of Android & Linux / Win8 & Win10 system change is done by
detecting the level of EINT3 signal. The voltage level of EINT3 should be kept stable during booting.
2. After boot up, the implementation of Android & Linux / Win8 & Win10 system change is done by
detecting the rising or falling edge of the EINT3 interrupt with the debounce time of 100ms. If the
interrupt event meets the condition, the module will restart and change over its USB mode for the
desired system.
5.5 USB Interface
5.5.1 USB Interface Definition
Pin#
Pin Name
I/O
Description
A13
USB_DP
I/O
USB D+ signal
A12
USB_DN
I/O
USB D- signal
A11
VBUS
I
USB power input
The L811-EA wireless communication module supports USB 2.0 interface. Before connecting it to the
Win7 system, it is necessary to install the USB driver (For Android & Linux system, no USB driver needed
but configuring the related kernel settings). After connecting the USB port to a PC, the USB driver resides
in the Windows system will map three ACM ports and four NCM ports, as listed below:
 2 ACM ports used for AT Commands.
 1 ACM ports used for LOG information captured by the debug software.

4 NCM ports are virtual network ports, mainly used for initiating data transmission serves.
Note:
One of the ACM ports can be used as a Modem COM port to initiate the data services. It is not
recommended to use due to the speed of Modem COM port is insufficient for the 100Mbps download
speed of the LTE standard. Only when the NCM ports are not available, the Modem COM port could
initiate the data service as the temporary solution.