The C80 as is from the factory uses just a depth transducer via the NEMA connection. The issue with that transducer is that the shallow depth alarm will not function. You need to upgrade to a DSM with an updated transducer to get full functionality. I installed a DSM300 with a B117 transducer when I upgraded several years ago.
Be aware that Raymarine had/has an issue with aging DSM modules primarily made in Mexico. Thanks to a tip from Firecadet, they replaced mine as well as his due to this manufacturing problem. I also needed to upgrade the power to the DSM and added an isolation relay to shut down the DSM when it is not needed. It draws quite a bit of current. I am still having an issue from time to time and will be replacing my transducer before I launch this year.
You may want to check to see if your C80 has the latest firmware just to make sure you are up to date.
Hope this helps.
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Jnizi![Image](http://pic100.picturetrail.com/VOL447/4900454/24798092/414460510.jpg)
2007 Vista 338 "Better Yet"
Previously:
2007 Vista 258 " Just Right"
2005 Horizon 230