Nmea connections

[theartfuldodger]

I was wondering if anyone could help me with the wiring for a nmea connection using a USB port. What I think is right is that terminal two is data out positive, terminal three is data in positive, and terminal 5 is common or ground. The cable which I have to hook into from the laptop is USB to serial adapter. Now the cable to hook into the USB adapter is wired different terminal one is common terminal three is data in positive and terminal four is data out positive. Should I rewire the cable.

[sailingdog]

It would help if you said what equipment you're trying to connect specifically, as some have quirks/issues others do not.

In general, the NMEA Out + wire from the GPS should connect to the #2 pin (RX data) on a DB-9 serial connector. THe NMEA In+ should connect to the #3 Pin (TX data). The only other pin that is typically used in an NMEA connection is Pin #5, the signal ground pin.

Garmin requires that the #5 pin be connected to the Garmin unit's 12 VDC ground or it won't work.

[theartfuldodger]

I'm connecting a nmea signal from a Ray Marine C80 system using the nmea wires to my Fugawi Marine system on my Toshiba laptop through a USB port using the USB to serial adapter.

[dreuge]

Hi,

I just connected my raymarine X-5 autopilot to my laptop via a serial to usb adapter. The link below will show you the pin diagram for the NMEA connection. I just made mine from an old serial cable I had. For the usb to serial adapter, I just purchased one on ebay for about $5.

I also added a cable ferrite, as recommended by raymarine. You can get these at electronic shops or from old computer cables. I cut mine off of a usb cable from a keyboard, slid it over the serial cable near the NMEA end and used a heat shrink tube to secure it.


Data Cable