Moderated Discussion Areas
  ContinuousWave: Small Boat Electrical
  Lowrance 520c

Post New Topic  Post Reply
search | FAQ | profile | register | author help

Author Topic:   Lowrance 520c
jimh posted 04-10-2008 11:14 PM ET (US)   Profile for jimh   Send Email to jimh  
I just finished a bench test of the Lowrance LMS-520c, which is a moderately priced combination instrument containing a 5-inch color display, a GPSr, and a SONAR:

Lowrance 500 Series GPSr, Electronic Display, and SONAR

Use this thread for any follow up question or comment.

jimh posted 04-11-2008 09:26 AM ET (US)     Profile for jimh  Send Email to jimh     
On the back of the LMS-520c (as well as on most of the other new models from Lowrance) there is a yellow connector marked ENET or ethernet. There is not much information in the manual about this connector, but my general understanding is that Lowrance intends it for linking to other Lowrance devices to permit data exchange at a much faster rate than could occur on the NMEA-2000 network.

Lowrance makes a new digital echo sounder, the Lowrance Broadband Sounder or LBS-1, which is housed in a separate enclosure, a so-called black-box sounder. The LBS-1 connects to a display device using the ENET connector. The display of the LMS-520c is then used to see the echograms from the LBS-1. I think you can also link two self-contained devices that have displays, and perhaps view the SONAR from another device this way.

While poking around the LMS-520c controls, I was surprised to see an IP address associated with the ENET port. It appears that Lowrance has IP networking capability via the ENET port. It would be interesting to connect a Lowrance device with ENET to a local area network and see what common protocols, if any, are supported. It would be much simpler to interface a complex device like a LMS-520c to a computer if the interconnection were via a standard unshielded twisted pair (UTP) ethernet 10-MHz network and IP network protocols were used.

The LBS-1 uses the IP address of

The manual for the LMS-520c makes reference to the ENET connector as "Network socket" and describes it as a "future enhancement."

phatwhaler posted 04-11-2008 10:23 AM ET (US)     Profile for phatwhaler  Send Email to phatwhaler     
Maybe the ENET jack is for hooking up a radar, or connecting a fly-bridge display.
jimh posted 04-11-2008 02:09 PM ET (US)     Profile for jimh  Send Email to jimh     
The documentation is a bit sparse on these new developments. This is a case where the product has gotten ahead of the published manuals. As I said, Lowrance intends the ENET for linking to other Lowrance devices to permit data exchange at a much faster rate than could occur on the NMEA-2000 network.

This explains the IP-addressing in the Lowrance ENET:


quote: - This is the "link local" block. It is allocated for communication between hosts on a single link. Hosts obtain these addresses by auto-configuration, such as when a DHCP server may not be found.

jmorgan40 posted 04-13-2008 08:43 AM ET (US)     Profile for jmorgan40  Send Email to jmorgan40     
I suggest you look at the 527 if that is the direction you are heading. For about $50 more it has a much more powerful sonar. Make a huge difference marking structure and fish. Talk to Kevin (minitauk), I believe he has the same unit.
jimh posted 04-13-2008 09:03 AM ET (US)     Profile for jimh  Send Email to jimh     
LOWRANCE has provided a resource for boater with a computer that runs the Windows operating system which allows a terrific emulation program to be run. The emulation provides a chance to test drive the device. A mouse click replaces a button push. The emulation is really quite amazing.

If you run the emulation and navigate to the menu choice which gives information about the software version, the software version number is given, along with the target. On the emulation software the target is Windows!

On there is a whole directory of software emulators for their products:

jimh posted 04-13-2008 06:29 PM ET (US)     Profile for jimh  Send Email to jimh     
Since I did not have any other NMEA-2000 devices on the bench to connect to the LMS-520c, I was only able to test its NMEA-0183 connection. To that end I used my Macintosh Laptop and its add-on serial port provided by a Keyspan High-speed USB serial port adaptor.

Interfacing the LMS-520c to the Macintosh was straightforward. The NMEA-0183 port is provided on a pigtail from the POWER connector. There are only four wires in the DATA cable:

Lowrance NMEA pigtail


Common = Shield
Not used = BLUE

On the Keyspan serial port there is a familiar 9-pin plug (i.e., pins, not sockets) with more or less the standard pin arrangement:

Keyspan Serial Port Pin Out

DB-9 Signal Type
1 DCD Input
2 RxDATA Input
3 TxDATA Output
4 DTR Output
5 Ground Ground
6 DSR Input
7 RTS Output
8 CTS Input
9 RI Input

So connection should be

LMS-520c to Keyspan


I wired up a 9-pin socket on the end of the Lowrance DATA cable with the connections above and gave it a try. Initially nothing much was happening. I had to configure the Lowrance LMS-520c to activate the serial port and send the correct NMEA sentences. After a few seconds--Success! The Lowrance GPS started talking to my Macintosh.

Here is a sample:


Jefecinco posted 04-14-2008 09:29 AM ET (US)     Profile for Jefecinco  Send Email to Jefecinco     

Do you think a comparison of the Lowrance to the Raymarine A60 is possible given the testing you have done so far?

Comparison testing of marine electronics seems to be very difficult to find. I, along with most I suspect, am unable to make a judgement based upon the specifications provided by the manufacturers. Your explanations on VHF radios makes that task easier but as to GPS or fish finders I'm in the dark. About all I can do is compare the in-store performance using emulator mode.


jimh posted 04-15-2008 08:50 AM ET (US)     Profile for jimh  Send Email to jimh     
Butch--You've asked a good question. I don't really know which device I would prefer. Each has its own advantages. Here is a very quick summary:

A60 Advantages

--soft key user interface. I think this will make operation of the device somewhat simpler and require fewer keystrokes

--digital SONAR. This should give better resolution to the echograms.

--meta-data companion files to screen captures.

--rugged construction. The Raymarine device is larger and everything seems a bit more heavy-duty.

LMS-520c Advantages

--LGC-3000 receiver has WAAS. However, this receiver does not seem to be quite as sensitive as the Raymarine RS12, which may diminish the advantage. Outside of North America, the advantage goes to Raymarine.

--NMEA-2000 networking. This is a double-edged sword, however, because if you don't have or don't plan to expand the network, it just adds complexity to the installation.

--compact size. The SONAR is built into the display, and this may make the installation easier on a small open boat.

--SONAR log recording. The Lowrance recorder is a very impressive feature, but it is only available for play back at the moment with the Windows operating system.

--higher resolution screen. The 480 x 480 screen, although slightly smaller on the diagonal than the Raymarine, has higher resolution, which produces a very detailed image

Because I only tested these units on the bench, I did not get any real experience in using them in actual application. There may be other considerations which I have not noticed or explored. For example, management of way way points or other user-entered data might be significantly better on one device compared to the other. Some devices allow for pre-planning of routes and uploading of the data. I did not explore those options.

Jefecinco posted 04-15-2008 09:41 AM ET (US)     Profile for Jefecinco  Send Email to Jefecinco     

Good points, thank you.

Cost is another factor to consider, IMO. The Raymarine digital sounder is reputedly a very nice feature. I believe it requires the addition of a digital sounder and transducer.

The Lowrance includes the sounder but as you point out it is not digital. However, I believe the yellow ethernet port allows athe addition of Lowrance's version of a digital sounder which must also be purchased. The standard 50/200 Skimmer transducer can be used with the optional digital sounder. Digital sounder performance with the Lowrance unit is also reputedly good but it is new and the jury remains out.

My older Lowrance does not do DCS as well as the new ones. Do you know if the 520C displays DCS data as well as the A60.

I agree that the Lowrance displays are generally very good for the cost.


jimh posted 04-15-2008 01:34 PM ET (US)     Profile for jimh  Send Email to jimh     
The Raymarine A60 includes the digital sounder in the package at the $999 MAP price.
jimh posted 04-16-2008 12:07 AM ET (US)     Profile for jimh  Send Email to jimh     
Butch--I am also curious to know if the Lowrance LMS-520c responds to NMEA input which contains the datagrams related to Digital Selective Calling (DSC). There are two datagrams in particular:

DSC Digital Selective Calling Information

DSE Digital Selective Calling Information Extended

ASIDE: Unfortunately, the precise details about these datagrams are not publicly well known because they are locked up in the National Marine Electrical Association (NMEA) standards, which are protected by copyright, and are, to the best of my knowledge, not available anywhere except by purchasing them from NMEA for quite a pretty penny.

The general understanding of the DSC and DSE datagrams is that they contain information about the location of a remote vessel which has been transmitted via a DSC radio. The initial DSC position reporting only provided for giving the position with an accuracy of about one tenth of a degree of latitude or longitude, which would be roughly about a mile accuracy. While this sort of accuracy might be useful for giving a position in the middle of the ocean, it did not take advantage of the accuracy of position generally available to mariners with a Global Positioning System receiver (GPSr). To expand the accuracy, the DSE datagram was added. This datagram gives extended data about the remote vessel location, giving a much more accurate position report.

As I mentioned (elsewhere), it would be great if manufacturers of electronic display devices which can accept NMEA datagrams would explicitly mention which of those datagrams can be interpreted and displayed. In the case of Lowrance, in their current documentation it is not clear how the LMS-520c will react to input of the DSC and DSE datagrams.

My suspicion is that there will be some more information coming on this, as Lowrance has begun to promote a feature they call Track-Your-Buddy.

Exclusive "Track-Your-Buddy" feature connects DSC position polling to Lowrance LCX, LMS and GlobalMap® units via NMEA 2000® to show the location of up to three boating friends on the GPS chart display

It would also be nice if manufacturers used the generic name for these features, which in this case would be just DSC remote position display, instead of their own names. I do have to give Lowrance credit for moving toward use of NMEA-2000 networking as the term for what they used to call "Lowrance-NET".

jimh posted 04-17-2008 09:39 PM ET (US)     Profile for jimh  Send Email to jimh     
When Lowrance says that their "Track your buddy" feature is an exclusive, they probably meant to enhance its value, but for me their advertising copy does just exactly the opposite. I really do not want to get involved with the "Track your buddy" feature at all if it really is something exclusive to Lowrance. What "exclusive" tells me is that it excludes all of my other boating friends who don't have the exact same Lowrance equipment. I want to invest in equipment that operates according to recognized standards and protocols. It would be far smarter for Lowrance to inform me that their new VHF Marine Band radio can provide the NMEA datagrams DSC and DSE via NMEA-2000 networking or NMEA-0183 serial connection, and that their multi-function display can accept the DSC and DSE datagrams an display the position of the remote vessel on a chart display.

If Lowrance told me that, then I would be certain that I'd could invest in their equipment and have it interoperate with other boats that have equipment that was in compliance with the standards of NMEA and SOLAS.

Whito123 posted 09-10-2008 01:53 PM ET (US)     Profile for Whito123  Send Email to Whito123     
Jim, thanks for posting your tests regarding the serial port. Any further ideas on how to get the unit connected to a regular network? For example, I'd like to have my Lowrance 527c connected to a regular router (I've got a WiFi 4-port router on board), so that I could use my laptop with a program like Coastal Explorer and be able to access the NMEA data, without having to use a serial cable hardwired to the Lowrance unit.


jimh posted 09-10-2008 08:49 PM ET (US)     Profile for jimh  Send Email to jimh     
Andrew--I am a little fuzzy on what consists of "a regular network."

If you want to make a wireless connection to a serial port, you probably need some sort of device for that purpose. I don't know if such a thing exists, but perhaps with some research you could find something that bridges RS-232 serial data to a wireless protocol.

Such a bridging device is outside the realm of the Lowrance 520c. The Lowrance 520c just knows about serial data on its NMEA-0183 port. If you want to access that via some other means, it is up to you to build the bridge, not up to Lowrance.

It would be quite useful to have a device that used Bluetooth, for example, to make a wireless connection between a data terminal device and a data communication device using RS-232 electrical connections. Again, that is something at a totally different layer than the marine electronics themselves. The Lowrance LMS-520c is ready to communicate via its NMEA-0183 serial data connection. If you want to adapt that to something else, you have to get creative.

Whito123 posted 09-12-2008 02:29 PM ET (US)     Profile for Whito123  Send Email to Whito123     
Thanks Jim.

By 'regular network', I'm referring to a typical internet protocol computer network. I've been able to succesfully connect to the Lowrance unit via serial cable, and have succesfully connected Coastal Explorer to use the NMEA data coming from the Lowrance unit over the serial connection.

I have purchased an RS-232/Ethernet adapter that would allow me to connect the Lowrance unit to a computer network by interfacing through an IP address assigned to the RS-232 adapter. This is a neat little piece of hardware that costs only about 75 bucks.

But, what I'd be interested in doing is making use of the ethernet connector on the back of the Lowrance device. It seems like I'd then be able to connect the Lowrance unit directly to a router via cat5, and thereby be able to skip the step of interfacing through the serial connection.

My search on the net hasn't yielded a cable to use to connect to the "enet" yellow port on the back of the Lowrance unit.

In the end, I'd like to be able to have my laptop, running "Coastal Explorer", gain wireless access (while on the boat) to the NMEA data coming from the Lowrance unit. If you haven't played with it yet, Coastal Explorer is fabulous, and handles NMEA data very well. It is a real benefit to navigation (my copilot can have it on her lap while I'm at the helm).

Hope this post gives you a better picture of what I'd like to do.


jimh posted 09-12-2008 08:07 PM ET (US)     Profile for jimh  Send Email to jimh     
Andrew--You've lost me. The "internet" runs on TCP-IP. It looks like the LOWRANCE device uses that networking. I've seen the control panel and there are IP-ADDRESSES involved.

Hoosier posted 09-12-2008 08:35 PM ET (US)     Profile for Hoosier  Send Email to Hoosier     
Now you've both lost me, isn't Ethernet a "regular" computer network? Doesn't the 520C have an Ethernet port, in addition to the NMEA 2000 port?
jimh posted 09-12-2008 09:26 PM ET (US)     Profile for jimh  Send Email to jimh     
We are very far afield from the Lowrance 520c review article and questions about it.

Ethernet is a low layer electrical protocol. You can run all kinds of data over it. Ethernet does not define anything about networks, applications, data protocols, connections, file transfers, and so on. Those all take place on much higher layers than the ethernet.

If this discussion of networking is to be pursued, let's move it away from this discussion about the Lowrance 5xx series. It really has no relevance.

SJUAE posted 09-13-2008 03:03 AM ET (US)     Profile for SJUAE    
Jimh--Great article certainly highlights Lowrance 520c capabilities. Given its price range it certainly is excellent value over other plotters with NMEA2000 capability.

May I suggest a google map to illustrate your point on map cartography vs charts?



jimh posted 09-13-2008 11:30 AM ET (US)     Profile for jimh  Send Email to jimh     
Steve--Nice link to GOOGLE Maps.

I think cartography is the next real battleground for marine electronics. The GPS receiver is now almost a commodity item. The physical displays are generally equivalent among brands in terms of size, resolution, and brightness in sunlight. Interconnection of devices tends to follow NMEA standards. The biggest variable by which devices differentiate themselves seems to be the digital cartography they use. This topic is probably best left for a separate discussion, so here I won't follow further down this path.

Regarding the LMS-5xx series and its ethernet connector, its purpose for now is to allow other devices to have a high speed connection into the unit for the purpose of using the LMS-5xx (and other Lowrance units with this feature) to display graphic output from those remote devices. At the moment the primary device seems to be the new Broad Band Sounder product. There may be other devices coming which will need to have high speed access to the display graphics, perhaps RADAR.

In general I think RADAR is somewhat off-topic in the context of small boat electronics. So, again, I'll leave further exploration on RADAR to others.

Just because there is a connector on the LMS=5xx series devices which uses ethernet, one cannot assume that there is the potential to connect to the device using ethernet as the electrical access into the device for purposes of communicating with it. For this to happen the device has to provide support for those connections and protocols. There does not seem to be any documentation for precisely what Lowrance has provided on their ethernet port. There is mention that TCP-IP addressing is used. Apparently those higher layer network protocols are in use. But this does not automatically mean there are application layer protocols supported by which you could gain access to the software used to configure the device.

I grant that it would be interesting if such a connection were possible. Perhaps Lowrance will move in that direction. But one should not conclude that just because a device has an ethernet unshielded twisted pair connection port, it suddenly supports all kinds of other communication protocols of higher layers or provides an application layer interface to control the device.

jimh posted 09-13-2008 11:39 AM ET (US)     Profile for jimh  Send Email to jimh     
When one says there is a "NMEA-2000" port, this implies a great deal of things. The NMEA-2000 standard provides a total specification for data communication, including electrical standards, connector standards, network standards, communication protocols, datagrams, self-configuration, and so on. Thus, when you get a "NMEA-2000" port you get all of those features, plus you get the certification from NMEA that the product will interoperate with other similarly certified devices on a network. The NMEA-2000 standard is far more comprehensive than "ethernet". "Ethernet" means, loosely, compliance with some part of the IEEE 802 standard. Cf.:

SJUAE posted 09-13-2008 02:35 PM ET (US)     Profile for SJUAE    

I agree the advantage of NMEA 2000 should be standardisation of connectivity and protocols etc.

Given that a standard backbone is approximately USD250 and USD500 for backbone and basic engine installation for gauge/sensors, is a reasonable investment on a small boat.

The Lowrance 520c can already exploit some of these features and negate/postpone the change out of old analogue displays.

The list of interfaces and add-ons is growing (eg usb)

It does not seem unreasonable to expect some bolder moves in the future to MAC/Windows based laptops for processing all inputs from engine/sensors/radar/gps etc for small boats. Giving us almost unlimited options

It’s around now for commercial use, maybe NMEA 2000 will help make it more feasible and less cost prohibitive.


jimh posted 02-12-2009 10:00 AM ET (US)     Profile for jimh  Send Email to jimh     
The Lowrance LMS-522C iGPS is currently being advertised for $499 at Cabela's. This is a significant reduction from their normal $649 price for the unit.
jimh posted 06-21-2009 03:32 PM ET (US)     Profile for jimh  Send Email to jimh     
In reviewing one of the screen captures used as an illustration in my article, I noticed something that had previously gone unmentioned: the Lowrance LGC-3000 GPS receiver makes note of which satellites it is apply the precision fix correction information provided by the Wide Area Augmentation System (WAAS). This can be seen in the screen shot linked below: screenCapture/GPS_Status.jpg

Note that certain satellite signals are marked with a yellow rhombus, indicating their data is being processed with correction information from WAAS.

PeteB88 posted 06-22-2009 02:54 PM ET (US)     Profile for PeteB88  Send Email to PeteB88     
[Deleted long narrative about many other devices but nothing to do with the Lowrance LMS 520c--jimh]

Post New Topic  Post Reply
Hop to:

Contact Us | RETURN to ContinuousWave Top Page

Powered by: Ultimate Bulletin Board, Freeware Version 2000
Purchase our Licensed Version- which adds many more features!
© Infopop Corporation (formerly Madrona Park, Inc.), 1998 - 2000.