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 Global Transceiver Module (GXM) Wireless Data Transceiver User Manual 
LUM0031AA Version 
1.0 
34 
(9)
 
L
OWPOWER 
M
ODE
 
The Lowpower Mode feature allows a MultiPoint Slave to consume less power.  This is achieved primarily 
by dimming the transceiver's LED’s. When set to 2 through 31, the transceiver will sleep between slots. 
For example, at a setting of 2 the transceiver sleeps 1 out of 2 slots; at a setting of 3 the transceiver 
sleeps 2 out of 3 slots, and so on.   
The following table shows the changes at different Lowpower Mode settings. The actual current draw 
depends on many factors. The table below gives only a qualitative indication of supply current savings. A 
low number reduces latency and a high number reduces current consumption. 
Current Draw 
Setting 
Description 
0 Lowpower, 
disabled 
LED’s dimmed, transceiver remains awake, transceiver is listening to the 
Master’s transmissions on every slot, and transceiver’s data port is shut down 
if the RTS line is deasserted (low). In this case, the transceiver needs to be 
awakened before it will be able to send data to the Master. 
LED’s dimmed, transceiver sleeps every other slot 
LED’s dimmed, transceiver sleeps 2 of 3 slots 
4-31 
LED’s dimmed, transceiver sleeps the number of slots corresponding to the 
setting. For example, with a setting of 31 the transceiver sleeps 30 of 31 slots.
More 
Less 
 
 
I
MPORTANT 
N
OTES
 
1. 
Lowpower Mode is used only in MultiPoint Slaves using serial protocol. Power savings occur only 
when the Slave is linked. No power savings occur when the Slave is transmitting data. Lowpower 
Mode is of little value when a Slave has a constant, high throughput. MCUSpeed must be set to 
‘0’ and RF Data Rate must be set to ‘3’ for Lowpower Mode to operate properly. 
2. 
Additional power savings may be realized when the Number Repeaters is set to 1. 
3. 
To communicate to the data port of a transceiver that is in Lowpower Mode, the RTS line must be 
held high to wake it up. The transceiver will wake up within approximately 20 milliseconds of 
when RTS goes high. 
4. 
If the RTS line on the Slave is held high, the transceiver will remain in normal operation 
regardless of the Lowpower Mode setting. Once RTS is dropped the transceiver reverts to the 
Lowpower Mode.  
5. 
If the transceiver has the DTRConnect option set to 1 or 2 and if the Lowpower Mode enabled 
(set to 1-31), the RTS line on the transceiver must be asserted for the ‘DTRConnect’ feature to 
operate properly. 
(A)
 
H
IGH 
N
OISE
 
The High Noise Option is useful in determining if out of band interference is affecting a radio link. A 
setting of 1 will provide a reduction of gain in the front end circuit thereby decreasing the affect of any out 
of band noise. The results will be seen as a lower signal value and a much lower noise value (as found in 
Radio Statistics or Diagnostics). If the noise is not reduced by a greater amount than the signal, the 
interference is most likely an in band issue.  
 
FreeWave Technologies, Inc. 
1180 S Flatiron Ct Ste F 
Boulder, CO 80501 
(303) 381-9200