what format coordinates do i have to use

If you use your unit to determine coordinates use this format “h ddd.ddddd” End result the coordinates would read to you as N 40.76224 W 73.97875. Just remember that when placing the longitude coordinates in your file, it should read as -73.97875.

The format to select as I mentioned "h ddd.ddddd" is the selection I have on my Nuvi 250w. I'm hoping you have something that is the same or similar in your 350.

Your nuvi may have the ability to change the format. Go to Where to? > down arrow > Coordinates and see if there's a button that is labeled "Format".

Otherwise, there are lots of online places to convert coordinates.

http://www.cosports.com/tools/gps_coords.htm
http://boulter.com/gps/
http://www.fcc.gov/mb/audio/bickel/DDDMMSS-decimal.html
http://www.jeeep.com/details/coord/

Coordinates can be expressed in several different formats. They are most commonly Degrees Minutes Seconds (DDD MM SS), Decimal Degrees (DDD.DDDD), or Degrees Decimal Minutes (DDD MM.MMM). The last format is the most common in current GPS models. The second one is the one we use in Custom POI files.

All of these coordinates are the same location.

Degrees, Minutes and Seconds
DDD° MM' SS.S"
N 32° 18' 23.1" W 122° 36' 52.5"

Decimal Degrees
DDD.DDDDD°
N 32.30642° W 122.61458°

Degrees and Decimal Minutes
DDD° MM.MMM'
N 32° 18.385' W 122° 36.875'

thanks, that did it. its formated for the right coords now, thanks again