
Smart Machine Smart Decision
4.7.3.1
Short circuit Detection
If a short circuit in the active antenna pulls V_ANT to ground, then the module will detect it, and the module will
report $GPTXT,01,01,02,ANTSTATUS=SHORT*6D sentence through the serial port. The customer should
check short circuit.
NOTE: The antenna supply voltage is not derived from VCC_RF.
4.7.3.2
Open circuit Detection
Firmware supports an active antenna supervisor circuit, which is connected to the pin DET_N. An example of an
open circuit detection circuit is shown in Figure 11and Figure 12. High (2.85V level) on DET_N means that an
external antenna is not connected, and the module will report $GPTXT,01,01,02,ANTSTATUS=OPEN*2B
sentence through the serial port. Low on DET_N means that an external antenna is connected, and the module
will report $GPTXT,01,01,02,ANTSTATUS=OK*3B sentence through the serial port.
Figure 11: Open circuir detection-A
SIM68R_Hardware Design_V1.02
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2013-01-22