A3LA-R-MIL-MOD User Guide Version B
Document Number: 451-93156-001A
21 of 159
peak current demand. Appendix F: Power Consumption provides the electrical power profile of
the A3LA-R.
The A3LA-R accepts 4.0 V to +5.5 V or +5.0 V to +32 V input. The A3LA-R is shipped with
hardware set for +5.0 V to +32 V input. It can be changed to +4.0 V to +5.5 V input through an
internal jumper—DISCONNECT POWER BEFORE RESETING THE JUMPER. Find the jumper by
removing the modem’s bottom plate. With the A3LA-R held in the position shown in Figure 2
(DB25 connector to the left), the A3LA-R is set for 4.0 V to +5.5 V when the red jumper is on the
middle and left pins, and it is set for +5.0 V to +32 V when the jumper is on the middle and right
pins. Each pin is also labeled with 5 V and 32 V to the left and right pins, respectively.
Note: You MUST remember the input voltage setting on the A3LA-R and not to apply voltage
above the maximum limit (of either 5.5 V or 32 V). The A3LA-R will be damaged beyond repair
with warranty voided if this were to occur.
Figure 2: Power Input Setting for the A3LA-R
IMPORTANT: You can remove the A3LA-R’s bottom plate to set the jumper but not for repair or
services. The warranty is voided if the A3LA-R is disassembled for any reason other than to set
the jumper.
2.4
P
OWER
O
N
/O
FF
C
ONTROL
With the EXT_ON_OFF pin left unconnected, the A3LA-R automatically turns on or off when
external DC power is applied or removed. Prior to turning the A3LA-R off, issue command
AT*P0 to ensure all memory-write activity is completed. When the A3LA-R is powered off, its
internal power-on-reset circuit requires two seconds for voltages to decay. Do not reapply
power until this time has elapsed. If the two-second wait time is not followed, the reset circuit
Red jumper used to
set input voltage
range
