FF Transducer Quandry

[Deeman]

I have a Datamarine L120 digital depth finder and a DX111-120 transducer, (http://www.eharder.com/Nova%20II/Misc/nova_645_lt.jpg) which is mounted through hull.
I want to install a Hummingbird FishFinder 535.
I read where one should not use two transducers. The DX-111 has a RCA plug, hence 2 wire. The Hummingbird (transom mount) transducer, (I believe) has 4 wires.
The Dilema; I don't want to drill another hole in the hull, nor seal up the one that is in there now.... Without,(cutting the off plug the transducer) shouldn't they all have 4 wires?
Are Sounder and Fish Finder transducers the same? http://www.eharder.com/misc/ponder2.gif
My question is; can I use the DX111 Depth sounder Transducer with or for the Hummingbird Fish Finder?
Anyone?
On a side note: I eMailed DataMarine and have not heard from them.
{This is also posted on another forum.}

[Victor Möller]

I see a couple of different problems, other than cable and connectors.

1. Two displays can not use the same transducer, they would need to know when to send a "ping" and when not to. If not, they would send pings and receive echoes to and from each other.

2. The frequencies are different, 200 KHz and 210 KHz

3. The power output from the 535 is much grater (250W RMS, 2000W P-P) then the power output from the DMI L120.

I guess there are a number of other differences as well. (beam width, impedance etc..)

Let me know how it works out for you! Happy fishing!

[Deeman]

I did hear back from Datamarine. But the response was to buy a handbook from them, no spec or tech talk. I have installed the Hummingbird transducer on the opposite side of the boat about 18" away and at the opposite angle of the hull.
This week end we'll see what happens when they are both turned on. If they operate on different ping frequency's then they should not interfere with each other.