Mytilene,
My earlier response was in error - sorry. You said depth - I somehow got speed in my head and responded with voltage reading for that type of transducer.
I have a friend that is a marine electronics installer. I'll ask him if the
Raymarine ST60+ series might interface to the SH transducer and post his response when he gets back to me.
In the meantime, do a
continuity check on the wires. That is simple and
free and may result in a happily inexpensive fix. The data wires are very small gauge - easily broken, or subject to corrosion over time and so much resistance that it can become virtually the same as a break.
Wayne