Wavenet Technology Pty Ltd. BM2900D 用户手册

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Boomer II User Manual & Integrator’s Guide __________________________ Appendix D - Application Development 
BM210012WT37 
123 
Copyright Wavenet Technology © November 2003 
Low battery  
Network contact is dropped when a low battery condition is reached. 
This occurs at the same time as a battery alert notification event, but 
after the assertion of the LOWBAT LED that occurs while the battery 
still has some remaining usable capacity. The time between these 
events (the assertion of the LOWBAT LED and the loss of network 
contact) is much influenced by the battery technology and the level of 
transmit activity within the wireless modem. A relatively inactive 
device provides more warning time than an active device. Also, an 
alkaline battery provides more warning than a NiCad battery. 
Low buffers  
If outbound SDUs remain unread within the wireless modem, its 
outbound buffers are eventually filled. When this occurs, network 
contact is dropped. Network contact is re-established when the internal 
buffer pool within the wireless modem reaches a usable level, as a 
result of SDU reads by the application. This situation never occurs 
when the client application reads continuously to clear the wireless 
modem of received outbound SDUs. 
Receiver disabled  
The client application can disable the wireless modem transceiver by 
using the Receiver Disable NCL command. When this occurs, network 
contact is dropped and the radio is turned off. Network contact is re-
established when the application issues the Receiver Enable, then the 
Transmitter Enable NCL commands. 
Power Management 
The following modem power management options can be included in 
an application to maximize battery life: 
Power Save Mode 
The wireless modem defaults to Power Save mode when turned on if 
the network supports the Power Save protocol. If you are concerned 
about latency of unsolicited outbound messages, you can turn off the 
Power Save mode, but at the expense of consuming more battery 
power. For details, refer to the NCL 1.2 command 
S_POWER_SAVE_MODE. See “Battery Life Considerations” and 
“Power Save Protocol” on the following
 page.  
Dynamically modifying the Power Save mode of the device is not 
recommended. 
On/Off upon User Demand 
To extend battery life, design the application to switch the modem on 
and off as the usage need arises. This method is especially effective for 
session-based, user-initiated applications.