Wavenet Technology Pty Ltd. BM2900D 用户手册

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Installation_________________________________________________ Boomer II User Manual & Integrator’s Guide 
 
Copyright Wavenet Technology © November 2003 
38 
BM210012WT37 
very fast transition between voltages, it may take up to 20 seconds for 
the modem to confirm a change in battery status. 
Message Waiting 
The Message waiting signal is held active low whenever there is at 
least one complete message waiting in the outbound buffers (including 
the reread buffer). 
In-Range 
The In Range signal is held active low whenever the modem is in 
range. It tracks the function of the Data Carrier Detect (DCD) signal.
  
Selecting & Positioning the Antenna  
Use this information to assist you in selecting the appropriate antenna 
to incorporate into your product package. For specific detailed 
information, Wavenet recommends that you use the expertise of an 
antenna design engineer to solve individual application concerns. Also 
always consult the appropriate technical representative of the target 
network operator prior to selecting and / or designing the antenna, so 
that it will pass network certification requirements. 
Antenna Safety 
The design of the integrated product must be such that the location 
used and other particulars of the antenna comply with the appropriate 
standards of the country in which the host/terminal is to be used. 
The integrator should refer to the statement of Compliance on page 9 of 
this manual and Regulatory Requirements section on pages 21-26 for 
country requirements. 
Mobile and Portable Devices 
In the environment where portable devices are in use, many variables 
exist that can affect the transmission path. In this case, it would be 
preferable to use a vertically polarized, omni directional antenna. 
Antennas for portable devices include the following designs: 
Internal antenna (invisible or pull-up)  
An internal antenna must provide a gain sufficient to meet network 
specifications. Cable routing from the modem to the antenna needs to 
avoid RF sensitive circuits and high level, high-speed clock circuits. 
Consider: 
 
The location of the antenna to avoid RFI to a computing device. 
 
Good shielding to the display and other RF-sensitive 
components 
 
The most efficient method of cable routing 
Otherwise, antenna gain can be offset by cable loss. A typical coaxial 
cable is very thin, such as RG178B used in portable devices, and cable 
loss can be 1dB or more per metre. Some coaxial cable manufacturers