Campbell Scientific AL200 ALERT2 Encoder, Modulator, and Sensor Interface - Manual (Page 29)

Appendix C. LED Indicators
The GPS LED is next to the GPS antenna connection. It can be used for
monitoring GPS power up and acquisition of a good satellite lock / fix.
TABLE C-1. GPS LED State Descriptions
State Description
Off
GPS module in “hibernate state”
Green GPS lock acquired (will only flash momentarily before turning off)
Red
GPS module on, No GPS Lock (or downloading almanac/leap
second information)
The Serial LED is located between the RS-232 and CS I/O interfaces. It can be
used for monitoring communication events on those ports.
TABLE C-2. Serial LED State Descriptions
State Description
Off
Neither interface is currently transferring data
Green RS-232 activity, Internal U0 activity
Red
CS I/O activity, Internal U1 activity
The Radio LED is located between the CS I/O and USB interfaces. It can be
used for monitoring the power and communication state of the radio interface.
TABLE C-3. Radio LED State Descriptions
State Description
Off Radio interface not currently in use
Green PTT applied, Transmitting
Red Power applied to radio, SW12V high
*When the radio is both powered on and transmitting, the red and green
LEDs will appear orange.
Under normal operation, the LED sequence should be as follows from
powering up the device through a data transmission:
a. GPS LED is red immediately after power, then flashes green
indicating that the AL200 has a GPS fix.
C-1