Hi, Everybody,

I am trying to set up an APRS station consisting of a Garmin GPSmap 60 and
one of the TinyTrak3 TNCs. However, the green 'GPS Valid' LED never lights.

I can connect the GPS receiver directly to my computer's serial port and
read good data, and I can capture some of that data and play it back from
computer to TinyTrak and the green LED lights up, but a direct connection
between GPS and TT just does not work.

I see a waveform coming out of the GPS serial (J2 pin 2 of the TT) using a
scope. Quiescent voltage is -5V, and when the data burst comes it is -5 V to
+5 V.

Could this be a voltage level problem on the serial? Is there a converter
that can be used? Or is it another problem, possibly protocol-related?

Any ideas?

Thank you,

Al W6LX