You are correct -- with the "powered cable", I was indeed referring to the yellow cable. And, looks like I overlooked the bit about voltage differences.
A pair of (series?) diodes & (series?) resistor, designed to drop the voltage from the output of the T2-301 from 5 to 3.3vdc. But going the other direction, would 3.3v be enough to be readable by the T2? The only cable that came with the Nuvi looks like a normal USB with a normal connector on one end and a USB-b "mini" on the other -- is that the one you are referring to? I can certainly cannibalize that. -- ER On 20-Aug-09, at 12:44 AM, Scott Miller wrote: > 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? >> >> > > > > ------------------------------------ > > Yahoo! Groups Links > > > -- Erich J. Ritzmann
