Wavecom WMOi3 User Manual

January 2001/ version 1.4
WMOi3 Integrated Modem
confidential ©
46/61
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8 General guidelines for the use of the WMOi3
8.1 Key information
8.1.1 Hardware and RF
• Ground plane: Wavecom recommends to have a common ground
plane for analog, digital and RF grounds.
• Length of the SIM interface lines (15 cm maximum)
• Bias of the Microphone inputs must be properly adjusted when
using audio connectors (mic + speaker) 1.
• EMC protection on audio input/output (filters against 900 MHz)
• ESD protection on serial link,…
• Possible spurious emission radiated by the application to the RF
receiver in the receiver band
8.1.2 The Antenna
The antenna sub-system and integration in the application is a major issue. It is a
major issue in the choice of the antenna cable ( type, length, performances,
thermal resistance, etc.)
These elements could affect GSM performances such as sensitivity and emitted
power.
The antenna should be isolated as much as possible from the digital circuitry
including the interface signals.
It is recommended to shield the terminal. On terminals including the antenna, a
poor shielding could dramatically affect the sensitivity of the terminal.
Subsequently, the power emitted through the antenna could affect the application.
8.1.3 Firmware upgrade
The WMOi3 firmware is stored in flash memory and it can easily be upgraded.
Two upgrade procedures are available:
• one (nominal) procedure based on the Xmodem protocol (AT+WDWL
command)
• one emergency mode (backup procedure) based on a Wavecom specific
downloader
8.1.3.18.1.3.1 Nominal upgrade procedureNominal upgrade procedure
The firmware file can be downloaded into the modem using the Xmodem protocol.
To enter this mode, the AT+WDWL command (see description in the AT command
manual) has to be sent to the WMOi3.
The necessary serial signals to proceed with the Xmodem downloading are:
Rx, Tx, RTS, CTS, GND.

Wavecom WMOi3 Specifications

General

Brand	Wavecom
Model	WMOi3
Category	Modem
Language	English