Humminbird Side Imaging Forums

Other Humminbird Products => GPS Chartplotters and Non-SI Humminbird Units => Topic started by: salika on July 21, 2014, 11:22:12 PM

Title: NMEA between 947c and VHS not working...
Post by: salika on July 21, 2014, 11:22:12 PM
Hello - I am trying to connect my Humminbird 947C to my West Marine VHS 580 radio so the radio can receive the boats current GPS coordinates, so far - no love - the radio makes no indication it is connected to anything.

On the Humminbird I have connected Power (of course), Speed/Temp, GPS Antenna, and 3D Transducer, the four plugs grouped together.. The 947C has NMEA Enabled in the Advanced menu, the GPS Wire to the antenna has a pig tail with a RED / WHITE / BLACK wires under a cap. The 947C is running software version 4.75.

The radio has two versions of its manual out there showing the NEMA+ wire as being either Yellow or Green and the NMEA GND as being the bare wire. I have connected both Green and Yellow and neither has worked.

I have made these connections;
   Humminbird White (NMEA+) to WM580 Yellow - not functional
   Hummingird White (NMEA+) to WM580 Green - not functional

   Humminbird Black (NMEA GND) to WM580 Bare
   Humminbird Red - not connected.

Per the discussion here ; http://forums.sideimagingsoft.com/index.php?topic=4014.0 (http://forums.sideimagingsoft.com/index.php?topic=4014.0)

I was thinking about trying the AS-HHGPS Cable in the second accessory port labeled #4 on page four of the 947C Manual. I was then going to connect AS-HHGPS White cable to the WM580 Yellow.

Is this the right thinking or should I be doing something else.
Thanks - Steve
Title: Re: NMEA between 947c and VHS not working...
Post by: Humminbird_Greg on July 22, 2014, 08:30:22 AM
Welcome to the Humminbird Side Imaging Forums salika.

Your wiring connections between your 947 and the VHB (?) radio sound correct.  Maybe you can find someone else with a Humminbird unit that would allow you to plug their unit into your connections to test it with?
Title: Re: NMEA between 947c and VHS not working...
Post by: salika on July 24, 2014, 03:45:31 PM
Hey Greg - thank you for the reply. Unfortunately I do not know anyone with a Humminbird unit I can try in place. I will be able to solder up a RS-422 cable and plug it into my laptop and read the 4800 baud / 8 bit / no-parity serial line that is coming out of the 947c. I will try that next week.  I am curious to three things I have read in other posts;

a) There is mention that if the Anttena has the older RED - WHITE - BLACK wires I might may need to upgrade to an antenna with the GREEN - YELLOW - BLACK wires, does this make sense?

b) There was also talk that this old NMEA-0186 unit output the UP command in the output sentence and this may make the output simply incompatible with some inputs.

c) The last is that there is a reason to splice into the antenna wires and directly attach to some other wire in that bundle.

Are any of these other suggestion applicable to my problem? I am still going ahead with the serial connection to make sure the 947C is outputting data.

Thanks - Steve
Title: Re: NMEA between 947c and VHS not working...
Post by: Humminbird_Greg on July 28, 2014, 11:50:36 AM
I don’t know if they apply to your situation or not Steve.  All three reference the same thing: the NMEA 0183 sentence prefix that we use.  With the older Red/White/Black wired GPS Receiver connection at the NMEA pigtail; the output was with an $IN prefix which most devices can use.  The newer GPS Receivers with the Green/White/Black wire connection have an $GP NMEA sentence prefix which some devices require.  This can also be taken from the older Red/White/Black wired GPS Receivers by splicing into the main cable (not the NMEA pigtail) as it has the Green wire connection there.
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