User's Manual

July 23, 2002 4-17
CreataLink2 XT Hardware Integrator’s Guide Hardware Integration
Power Management
Power Management
Make power and ground electrical connections via the 22-pin connector. Minimize
cable length to limit the voltage drop across the cable during RF transmissions.
The host must provide continuous dc power to the data transceiver. It resets if the
power source is interrupted. The data transceiver uses the built-in power-saving
capability of the ReFLEX protocol that enables it to spend the majority of the time
in the sleep mode.
States of Operation
The host power supply provides source current to the data transceiver. There are
four data transceiver power consumption states:
• Off—The data transceiver is off, or the host-supplied power has failed.
• Sleep—The processor is sleeping and wakes up to an interrupt, but the RF sec-
tion is off.
• Receive— The processor is actively processing information. The RF sections
are on and demodulating data.
• Transmit—The processor is actively processing information. The RF sections
are on and transmitting data.
The data transceiver automatically powers up and enters the sleep or receive state
when supply voltage is applied.
Power Profile
Network Configuration System/Data Transceiver
Battery-Save Cycle
Both the network configuration and the data transceiver configuration affect the
percentage of time the CreataLink2 XT device spends in the sleep and receive states.
In a two-way paging network, the battery-save cycle is a configuration parameter
stored in the data transceiver and defined for the overall system.
Assume the system battery-save cycle parameter is ‘n’ and the data transceiver
battery-save cycle parameter is ‘m’. The data transceiver typically wakes up to
receive messages every 2
m
frames, where a frame takes place every 1.875 seconds,
and the network schedules transmissions to the data transceiver at the times when
it is awake to receive.
In situations where the outbound network loading is such that data transceivers
are required to be awake more often, the system can dynamically modify data
transceiver behavior. It can broadcast a system battery-save cycle that causes all
data transceivers to wake up for the lesser of every 2
n
frames or every 2
m
frames.
For example, if the mode battery-save cycle parameter is 3 and the system battery-
save cycle parameter is 7, then the data transceiver would wake up every 2
3
, or 8
frames, and then revert to a sleep state. If the network determines that all data
transceivers on the network need to be awake more often, the network could
broadcast a system battery-save cycle parameter of 1. All pagers would respond by
waking up every 2
1
, or 2, frames to receive data. Once the system loading was
reduced, the network could broadcast a system battery-save cycle parameter of 7,
and the data transceivers would react by falling back to their own internal battery-