Specifications

Chapter 6 – Application Considerations
16
Chapter 6 – Application
Considerations
General Guidelines for the Use of the SocketModem
Hardware and RF
· Ground plane: Multi-Tech recommends having a common ground plane for analog, digital and RF
grounds.
· ESD protection on serial link, …
· Possible spurious emission radiated by the application to the RF receiver in the receiver band
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.
Multi-Tech recommends shielding 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.
Firmware Upgrade
The SocketModem firmware is stored in flash memory and it can easily be upgraded.
The upgrade procedure is based on the Xmodem protocol (AT+WDWL command).
Nominal 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
SocketModem.
The necessary serial signals to proceed with the Xmodem downloading are: Rx, Tx, RTS, CTS, GND.
Initial Configuration Using Mobile PhoneTools
For initial configuration of your wireless device, Multi-Tech offers a Windows-based mobile
PhoneTools application.
To load Mobile PhoneTools, click the Mobile PhoneTools icon on the system CD and follow the on-
screen prompts.