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Author Topic:   Interface of PS1000 VHF Radio to Lowrance LMS-334c NMEA Bus
davej14 posted 03-24-2006 01:07 PM ET (US)   Profile for davej14   Send Email to davej14  
After purchasing a PS1000 VHF radio I am now looking for the best combi sonar/gps unit to interface with it so that I can take advantage of the DSC calling features of the radio. Ideally I would like to interface the radio with the new Lowrance 334C sonar/gps with internal antenna. The problem I see is that Lowrance devices output their data to a NMEA2000 bus while the radio has separate leads compatible with NMEA-0183 ver 2.0 or higher.

Does anyone have any ideas for getting these two systems to work together? I am holding off purchase of the Lowrance unit until I understand how it could be interfaced to the radio.

ratherwhalering posted 03-24-2006 01:23 PM ET (US)     Profile for ratherwhalering  Send Email to ratherwhalering     
Dave, my Garmin 168 Sounder has NMEA 0183 and RTCM 104 DGPS corrections and outputs. I pluged it into my PS1000, and it worked just fine, allowing all DSC calling features.
ratherwhalering posted 03-24-2006 01:24 PM ET (US)     Profile for ratherwhalering  Send Email to ratherwhalering     
Nevermind, I just figured out what you were asking, and my application is obviously not applicable.
Chuck Tribolet posted 03-24-2006 02:05 PM ET (US)     Profile for Chuck Tribolet  Send Email to Chuck Tribolet     
Looks like you are going to need a NMEA-2000 to NMEA-183
converter. Dunno if such a product exists, but I wouldn't be
surprised if it did. I'd guess about $50 for a simple one.

Note that the two are electically very different. NMEA-183
is more or less just a serial port, NMEA-2000 is a thing call
CAN bus that comes from the automotive world.


JMARTIN posted 03-24-2006 05:17 PM ET (US)     Profile for JMARTIN  Send Email to JMARTIN     
The Lowrance 332, 337, and 335 have one NMEA-183 port along with the NMEA 2000 Bus.

I have used the one NMEA 183 port to hook my Navman flow meter to the GPS.

I just ordered a PS 1000, I wonder what will happen if I hook it to the same port? The Navman just receives information from the GPS, it looks like the radio will receive and send information to the GPS.

All this stuff is a bunch of gobbely gook to me, but I think the Navman is communicating with the GPS now that I got the correct wires hooked up. The Navmans instruction book was incorrect. John

Chuck Tribolet posted 03-24-2006 06:08 PM ET (US)     Profile for Chuck Tribolet  Send Email to Chuck Tribolet     
JMartin: You can generally connect one NMEA output (the GPS)
to a few inputs (four?).

Current Navman manual is correct, IIRC.


jimh posted 03-25-2006 12:59 AM ET (US)     Profile for jimh  Send Email to jimh     
You may be able to use one NMEA-0183 output to drive two NMEA-0183 inputs. If you have a problem you can get a NMEA-0183 buffer/distribution amplifier.
davej14 posted 03-25-2006 10:55 AM ET (US)     Profile for davej14  Send Email to davej14     

I checked the product manual for the Lowrance LMS-332c and it looks encouraging. Your are correct in that it has both the NMEA-2000 bus AND a single NMEA-0183 I/O port. This is great news. Your installation is almost exactly what I have in mind, except I will utilize the NMEA-2000 bus with a Lowrance flow meter. I was at BassPro looking at the LMS-334c (with internal GPS antenna) but didn't think to look at the power cord which is where the NMEA-0183 I/O cables are bundled. Now I will have to go back unless someone here has this unit and can let me know it it also has the MEMA 0183 port. The operating manual for this unit is not yet on the Lowrance website.

In your case you should be in pretty good shape because you will only use the input pair of the NMEA-0183 port for your navman flow meter (the LMS-332c only needs to receive data from it). The output pair of the NMEA-0183 port can be connected directly to the PS1000 to provide your position data for PSC calling. What you will not have with your configuration is position information on other vessels. That data would be an output from the PS1000 and you have already used the input pair on the LMS-332c for your flow meter. By utilizing the Lowrance flow meter I will be able to have a two way data path between the PS1000 and the LMS-332c.

You can connect the output of a NMEA 0183 port to multiple inputs but each input must be connected to a separate output. Another way to look at this is that the outputs send the same data simultaneously to the inputs they are connected to, but the inputs can only receive one data stream at a time. If the inputs were connected to more than one output, the data from different devices could arrive at the same time and be corrupted. The limitation of how many inputs can be connected to a single output is determined by how much current the output is capable of delivering. I believe the correct number is four. If you connect to more than that, the output will not be able to maintain the necessary signal (voltage) level for valid data. To solve this you can add a "buffer" device which basically repeats the output signal but has higher output current capability.

Sorry for the length of this post.

FRSam posted 03-27-2006 03:47 PM ET (US)     Profile for FRSam  Send Email to FRSam     
Dave I wish I could be of more help but I just got off the phone with Lowrance and they said there should be no problem at all connecting the LMS 334c to either the Icom M-402s or the PS1000 VHF radio. They are very compatible and he went on to say no converter is necessary.

You might want to give Lowrance a call ph # 800-324-1356.

Good Luck,


JMARTIN posted 03-27-2006 04:40 PM ET (US)     Profile for JMARTIN  Send Email to JMARTIN     
Dave, my Navman needs to receive information from the GPS. The Navman needs to know how fast you are going to figure out mpg and for the logs to work. I think the GPS will need to be able to send and receive information from the radio. It sends to the radio where it is right now, and then if someone calls, if they are set up so the radio knows where they are, it will show you on a map where the boat is that is calling. I think that is how it works. If so, an extra benny. I bought the radio for space and inability to hear my existing one above the roar of Old Smokey. John
Chuck Tribolet posted 03-27-2006 07:08 PM ET (US)     Profile for Chuck Tribolet  Send Email to Chuck Tribolet     
"then if someone calls, if they are set up so the radio knows where they are, it will show you on a map where the boat is
that is calling." is not how it works.

If you push the distress button it sends your position.

If you send a position request to another radio, and it's
setup to either automatically reply, or the human at the
other end approves, it sends its position back to your radio,
and your radio passes the position to the GPS which displays

And vice-versa for someone sending you a position request.


JMARTIN posted 03-27-2006 07:42 PM ET (US)     Profile for JMARTIN  Send Email to JMARTIN     
Well, I was close. I guess your map could get quite crowded if alot of people were on these new fangled communication devices. Thanks for the explaination.


davej14 posted 03-27-2006 07:45 PM ET (US)     Profile for davej14  Send Email to davej14     
OK, I spent some time on the phone with Lowrance, Standard Horizon and Garmin today. Here is what I learned regarding the interface with the PS1000. Chuck's previous post has the information "flow" stated correctly. In order for the PS2000 VHF to pass position data from another craft along to your plotter/sonar/gps display, it uses NMEA 0183 word type DSC and DSE. The Lowrance 33Xc series are not set up for this word format. According to Standard Horizon this is a "longer" word that is becoming more popular and their own units (no surprise) and some Garmin units will "understand" the DSC and DSE format.

There is no problem with the PS1000 receiving gps data from the output of Lowrance 33Xc series because the Lowrance unit will send with an RMC data sentence. This is the preferred data sentence format for the PS1000 input.

After pricing the options for Lowrance, SH and Garmin, I have personally concluded that the Lowrance 33Xc (specifically the LMS-334c-igps) is the best value AND it is available today. Although the screen of the 334c will not display the position of a craft sending an emergency DSC call OR receiving a call request from me, my understanding is that the lat and lon would display on the PS1000 RAM+ mic. You would just have to manually enter the position on the gps to navigate to it.

Chuck Tribolet posted 03-28-2006 09:00 PM ET (US)     Profile for Chuck Tribolet  Send Email to Chuck Tribolet     
Those are NMEA "sentences" not "words".

The DSC sentence has been around quite a while. My SH
Spectrum manual is dated Jan 2000 and the radio generates it.
The DSC sentence is sufficient to locate the other boat
within one minute of lat/lon (about a mile). The DSC
sentence was not invented by SH -- it comes from a standards
committee. The DSE sentence is newer, and has considerably
more accuracy. But chartplotters have been handing DSC at
least since the SH 150 came out.

Lowrance is just behind the times (so is my Garmin 162, it
doesn't handle the DSC sentence either). Who knows, Lowrance might
do a hfirmare update (no HW is required) to handle it. Garmin did
on some models, but not the 162.


kalbo posted 04-21-2006 10:26 PM ET (US)     Profile for kalbo  Send Email to kalbo     

I have a Uniden 525 and am trying to hook up a Lowrance 337 DF to it. The Lowrance manual says that the yellow wire should be hooked up along with the shield ground, basically a two wire connection. The Uniden as a yellow and white wire for 183 - and a green and orange wire for 183 +. Which wires do I connect to? I'm lost please help


Chuck Tribolet posted 04-22-2006 08:57 AM ET (US)     Profile for Chuck Tribolet  Send Email to Chuck Tribolet     
The radio has NMEA IN and NMEA OUT. Each of these has + and

Lowrence yellow wire to Uniden NMEA IN + (white)
Lowrance shield to Uniden NMEA IN - (yellow)


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