My question is this. I have an HDS-7 unit at my steering wheel and a LCX-112C at the front of my boat. I am trying to network the 2 together but I am having trouble. I spoke with Lowrance technical support and they told me all I needed was the NMEA2000 starter kit.
The way I have it wired now with the components that it came with is this. Starting from the back of the boat it is tied to the positive and negative. It goes to the fuse supplied in the kit. That goes on to a �T� connector. The bottom part of the �T� connector uses the 2�ft lead and goes to me HDS-7 at the steering wheel and the 15�ft other lead goes out the other side of the �T� connector to the front of my boat. It ties in to another �T� connector and the bottom part of that one goes to my LCX-112C. The other side of that �T� connector has the end resistor on it.
What am I doing wrong? It isn�t supplying power to either unit. I really need help figuring this out. I downloaded a wiring diagram from Lowrance that shows you how to install a network and I read over it. The only thing I can think of is that maybe I need to buy a power node and install it before the HDS-7. Any help or suggestions would be greatly appreciated.

Per your description, you already have the NEMA network being supplied with power from the back of the boat. You only want ONE source of power on the NEMA network. I believe that your LCX also has the capability to power the NEMA network via an extra set of leads on its power cable. Is yours a red or blue network? If it is a red, and if you are going to use the power node and not your LCX unit to power the network, and if the starter kit only came with two T-connectors, then you will need to get another T or a double T-connector in order to be able to hook everything up correctly. There should have been two 120ohm terminator's in the red starter kit, one for each end of the network. Also be sure and run the power cable for the NEMA network through a switch so that you can shut it off as it will continually draw power whether being used or not.

mine is a red network that I am trying to run. I am trying to run everything through the HDS-7 first because I don't have a transducer or GPS puck for the LCX-112c. I know that if it's networked right I can use the transducer and the internal GPS from the HDS unit.

The NEMA network will not allow you to share the transducer, it does not have the bandwidth required to do that. If you are wanting to do that it must be done through the ethernet network.

Re-read your original message and find this point rather confusing "It isn�t supplying power to either unit". The power node is only used to provide power to the network and not the units, they of course will also need their power cables hooked to a 12 volt source.

This is the response I got from Lowrance. It was their tech support on the phone that told me the HDS-7 with a power node will supply the LCX unit with transducer readings, power, and GPS if hooked up with the nmea 2000 starter kit and a power node. I asked them the same exact question that I posted in this forum at the top of this discussion and this is the response I got back from them today. It is right Below this.

Thanks for contacting us.

There needs to be a T connection for each device on your network. One for each unit and any sensors that may be on your network also. With the 120 Ohm terminators on each end of the network. If you have just the LCX and HDS units on the network you would need 2 T's and the power on the network would be supplied by the LCX unit.

Please feel free to contact us if we may be of further assistance.

Lowrance Customer Service
Division of Navico Inc.

I'l be super T'd off if the red network wont provide sonar to the LCX unit from the HDS. That would mean I've been ordering all kinds of useless [censored] and waiting and waiting for stuff to show up. This stuff better some how work as I've already gutted all the other wires from my old fish finders and I've been dropping all kinds of money ordering T connectors and 2'ft lead wires. It's really totaling p. I really wish I new someone who could tell me absolutely Yes it will work; or Hell no. Stop what your doing and send that [censored] back before you can't return it.

To accomplish what you are trying to do will require both the Ethernet and NMEA networks to be operational. The Ethernet network will allow you to share the sonar data between the two units and the NMEA network will allow you to share waypoinst and to utilize the HDS's GPS antenna. This statement from Lowrance customer service is absolutely correct "There needs to be a T connection for each device on your network. One for each unit and any sensors that may be on your network also. With the 120 Ohm terminators on each end of the network. If you have just the LCX and HDS units on the network you would need 2 T's and the power on the network would be supplied by the LCX unit". Unlike the HDS unit, your LCX unit has the capability of supplying the NMEA network with the power that it requires, this would eliminate the need for the separate power node. If you look at the power cable for you LCX unit you should see that it splits into three branches, one is used to provide power to the LCX unit, one to provide power to a NMEA 2000 network and the third is the data cable for the older NMEA 183 network. You will always need the branch that provides power to the LCX to be hooked to a 12 volt source. If you want the LCX to provide power to the NMEA network then that branch should be hooked to a 12 volt source. Here's what I would do, hook both the LCX power and LCX NMEA branches to a 12 volt source, hook one end of the 2' NMEA cable to the back of the LCX and the other end to the bottom of the T-connector, install one of the 120 ohm terminator's to one of the ports on the same T connector, hook the long extension cable to the last port of this same T-connector. On the other end of the long extension cable hook up your other T-connector, hook one end of a 2' extension cable to the bottom of the T-connector and the other end of it to the back of the HDS, install the second 120 ohm terminator to last open port on this same T-connector. Buy a Lowrance Ethernet cable and hook one end to the back of the LCX and the other end to the back of the HDS. Hope this helps.

I'll give it a try. I need to order the ethernet cable and another 2'ft cable for the nmea2000. You have any idea who actually has this stuff in stock?

Not sure who might have them in stock but I would check with a few of the board sponsors to see if they can help. One question that I failed to ask is why do you want to share the sonar data with your console unit instead of just adding a second transducer mounted to your trolling motor. Not sure what kind of fishing you do, but I fish brushpiles a lot and seeing what is directly below me is much more useful than what is 18 feet behind me. Also, not sure what kind of NMEA connection is on the back of the LCX unit, it may be a different cable than what the HDS uses. It is possible that the T-connector will hook directly to the back of the unit without the extension cable. This would leave it kind of exposed, but at least you could hook it up and test it before buying anything more.

I'm trying to use the internal GPS and transducer from the HDS-7 becuase I traded a guy on the forum some guns for the LCX-112c and he needed the puck and transducer for a LCX-113 that he was keeping on his boat. When I called Lowrance they told me it could be done useing the HDS for ducer and GPS so I went ahead and traded. The LCX-112c works great and is a beautiful unit. I just need to get it working with the HDS unit. Until you I hadn't gottin a staight answer from Lowrance or any helpful suggestions as this is all new to me. The T connector does fit behind the LCX unit. I'll try wiring it to power and feeded it first and then to the HDS unit when I get home. Do I have to change any settings in the units for them to recognize each other; or will the LCX unit automatically lock on to the GPS?

Not real sure about the LCX setup but would expect it to be similar to the HDS. You will need to go into the network settings menu and enable both the send and receive waypoint options for the NMEA 2000. Then go to the "Data Sources" menu and select the GPS option. Highlight the HDS unit and press the menu key. Change the scope to global. I will try and look at my HDS tonight and make sure that I'm not forgetting something. Also if you did not get the manual with the LCX then you may want to go to the Lowrance website and download it. It should explain how to setup the LCX unit. You probably should also check on the same site and confirm that both of your unit are running the most current software. Just as a heads up, like the NMEA cables, they are rather proud of the Ethernet cable, for about $15-20 more you could just buy another transducer for the trolling motor. Hopefully Jason Gilstrap will check in before long and point out anything that I might have overlooked or stated incorrectly.

I wired up the 2 units with NMEA 2000 kit the way you said and waalla. The GPS picked up and locked on to my position. Thank god! Now the next gorilla to tackle is the Sonar. Like you said just above; buying another transducer may be the best option. It would probably be better anyway for on the spot fishing of brush piles and rock beds. Drop offs and structure; what not. I'll look into seeing how much another transducer cost.

Glad you got it working. Whether you decide to get a new transducer or share with the HDS it will be a lot more straight forward than the NMEA setup. The Ethernet network is just the single cable that attaches directly to the back of each unit. There are no T-connectors or extension cable�s or power node's or or terminator's or anything else required. Just my opinion, but I think you would be a lot happier with just having a second transducer mounted on your trolling motor.

Everyone I've spoken to so far has recommended the transducer at the front which I'm sure I will do after thinking about it. It just makes since to have an acurate reading of what's right below you when you have that much money invested in all this. Is there any other reasons to use the ethernet cord? If there is I'll install both.