When performing an inventory in a warehouse or caring for patients in a hospital, it is probably too cumbersome—if not impossible—to plug your mobile computer into an electrical outlet. Therefore, you will need to depend on the computer’s battery. The extra load of the radio card in this situation can significantly decrease the amount of time available to operate the computer before needing to recharge the battery. The operating time, therefore, might decrease to less than an hour if the client device accesses the network often or performs other functions, such as printing.
To counter this problem, most vendors implement power management techniques in the client devices and radios. Without power management, radio-based wireless components normally remain in a receptive state, waiting for any information. For example, some vendors incorporate two modes to help conserve power:
- Doze mode: The doze mode, which is the default state of the product, keeps the radio off most of the time and wakes it up periodically to determine whether any messages await in a special mailbox. This mode alone generally uses approximately 50 percent less battery power.
- Sleep mode: The sleep mode causes the radio to remain in a transmit-only standby mode. In other words, the radio wakes up and sends information if necessary, but it is not capable of receiving any information.
When deploying wireless client devices, such as bar code scanners, for performing regular functions, such as inventory control, plan on installing battery recharge stations. When the client devices are not in use, the client devices can be left in the charging station. That way, they’ll be ready to go when they are needed.