User`s manual
Tracker3 User’s Manual 10
7. Jumper Settings
A jumper block on the OT3m board provides the following settings:
Voltage select – ‘5’. Connects pin 4 of the serial connector to the
output of the 5-volt regulator. Use this setting to supply power to
a 5-volt GPS receiver or other external device.
Voltage select – ‘12’. Connects pin 4 of the serial connector to the
input of the 5-volt regulator. Use this setting to supply
unregulated power from the radio connector to a GPS receiver, or
to supply power to the tracker from the serial connector.
‘HI’ – This jumper sets the audio output level to the high range.
This is needed mostly for mobile radios, especially some
commercial models.
‘HT’ – Selects if push-to-talk signaling through the audio output
line is enabled. Use this jumper with most HTs by Icom, Yaesu,
and Alinco handhelds, but not Kenwood.