Campbell Scientific AL200 ALERT2 Encoder, Modulator, and Sensor Interface - Manual (Page 27)

Appendix B. Cables and Connector Pin Descriptions
TABLE B-5. Radio Interface Pin Description
Pin Function
Freq. Select Frequency Select. Accommodate frequency selection during
operation by grounding selected pin on radio interface.
SW12V Switchable radio power supply
PTT Push-to-talk. Grounded during transmission.
G Ground
TX Transmit audio output
B.6 Sensor I/O Interface
The sensor I/O interface is a 5-pin screw terminal. A mating connector is
supplied (pn 28750).
TABLE B-6. Sensor I/O Pin Description
Pin Function
SE1 Analog voltage / current input
SW12V Switchable sensor power supply
P1
Switch closure input. Internally tied high to 5V.
G Ground
C1 Digital I/O for high/low status or SDI-12
B.7 GPS Input
The GPS input is a threaded SMA female connector.
TABLE B-7. GPS Input Pin Description
Pin Function
Center Conductor Socket RF Input, biased by 3.3 V for use with active
antennas
Shield RF ground
B-3