Digital Marine Depth Sounder - remote display help!

[mdrifter]

The above depth sounder can drive two remote displays...The (US) manufacturer is no longer in business and we need to wire up a remote display for easier reading in the cockpit. Can anybody tell us which display will work and how to connect it, please? There is no wiring diagram for the instrument and the output is thought not to be NMEA but the "manual" does say it's 16 bit serial. The connector(s) have three pins...HELP!!

 

[mdrifter]

I got the name wrong...should have been Datamarine and it appears they've been defunct since c.2000. Managed to track down www.dmimarine.com who may be best bet for repair/replacement and remote display...