Ok, back up for a minute. What cables are you using? Are you connecting directly to the T2-301, or are you using the yellow and black cable?
The nuvi needs 3.3v levels. If you're connecting it to a T2 of any type, you need to either use the Garmin cable with the level shifter built in, or use a couple of diodes and a resistor to limit the output level. Scott va3xto wrote: > > > I wired up a T2-301 with a powered cable using two USB-b connectors. > > Serial pins 4&5 supply power to pins 1 &5 of USB-b-B (5 vdc power on back) > > Serial pin 2 connects to pin 3 on USB-b-A (FMI on side). > Serial pin 3 connects to pin 2 on USB-b-A (FMI). > > 8.06k measured resistance between ground and USB-b-A pin 4 brown. > > The Nuvi gets power from the back, no problem. Disconnecting back yields > serial device must have power, yada, yada. > > The GPS is working based on the map it displays on the Nuvi itself. > > The T2-301 doesn't seem to send any data using the Nuvi. (And, > transmitting packets nearby from another machine does not display the > expected waypoint.) > > Before plugging in the Nuvi, I had the T2-301 transmitting APRS packets > using the ADS-GM1 GPS. > > Any ideas what I am missing? > >
