HUAWEI ME909u-523 LTE LGA Module
Application Guide
Overview
Issue 04 (2014-12-08)
Huawei Proprietary and Confidential
Copyright © Huawei Technologies Co., Ltd.
10
Application
Mobile equipment
network
1.2 Basic AT Command Processing Principles
1.2.1
Ports
The ME909u-523 module provides four ports to interact with its host:
MODEM port: simulated using USB, for AT command interaction and
establishing data connection.
Port name: HUAWEI Mobile Connect-Modem
PCUI port: simulated using USB, for AT command interaction only.
Port name: HUAWEI Mobile Connect-PCUI Interface
ECM port: simulated using USB, for establishing communication connection.
Port name: CDC Ethernet Control Model (ECM)
NMEA port: simulated using USB, sending unsolicited indications for NMEA
positioning data and sending GPS AT command.
Port name: HUAWEI Mobile Connect-GPS Interface
NOTE
The ME909u-523 module does not support the modem dialing-up.
The ME909u-523 also provides a port for debugging:
DIAG port: Simulated using USB, for DIAG (diagnostic) command interaction
(mainly used to debug modules at present).
Port name: HUAWEI Mobile Connect-Application Interface
A host controls a module using AT commands. If AT commands are unavailable, a
module can be deemed as unavailable.
1.2.2
AT Command Processing Mechanism
A module processes AT commands from the ports (MODEM, PCUI, GPS and UART)
in series. An AT command can be processed when and only when the previous AT
command processing has been completed. If the module is processing an AT
command, a new AT command from the same port will be ignored and other
commands from other ports will be buffered until the current AT command is
processed.
