User`s manual

Tracker3 User’s Manual 45
19. Telemetry
All Tracker3 models have the ability to send telemetry information from their on-
board sensors, and some models include external analog and digital telemetry
inputs.
The OT3m and T3-301 can measure and report their supply voltage, and all
models include a temperature sensor – though the on-board sensors on the T3-
135 and T3-301 reflect the temperature inside the radio enclosure, and are
generally more useful for monitoring the condition of the equipment than the
ambient temperature.
When telemetry reporting is enabled, the tracker transmits standard APRS
telemetry reports in the following format:
T#sss,aaa,bbb,ccc,ddd,eee,76543210
The ‘sss’ field is a sequence number that increments with each report. Fields
‘aaa’ through ‘eee’ encode five channels of analog readings from 0 to 255, and
fields 7 through 0 are binary bits, either 0 or 1, representing digital inputs.
The ‘aaa’ field represents the tracker’s supply voltage, and fields ‘bbb’ through
‘eee’ correspond to inputs A1 through A4 respectively. For the OT3m, all
voltages are reported in 1/10 volt units.
While the T3-135 board has no externally accessible analog inputs, four pads
marked A1 through A4 are present on the board and may be used for analog
telemetry, with readings of 0 to 255 representing 0 to 5 volts.
Digital bit 1 reflects the state of the OT3m’s terminal block ‘IO’ pin, and bit 0
indicates the configuration profile currently in use.