Most transducers are made by Airmar, but the plugs are different in some cases. I have a Simrad unit but the transducer is a Furuno (made by Airmar) . I had to buy an adaptor to connect the ducer to the sounder. Impulse was bought by Uniden many years ago. This guy got zero bids on this last time it was listed, might be worth a shot....
http://cgi.ebay.com/ws/eBayISAPI.dll...tem=7207017006