Hi guys...

I have/need spares for a B&G Hercules 390 system.

I need to know if possible to interface Dataline/Simrad type speed
and depth transducers into the Hercules computer. Any input? The
post above might be very helpful for speed, what about depth signals??

Is the protocol similar between brands (esp of early 90's vintage)??

I HAVE perhaps some extra Stowe/ Dataline/ Robertson/ Simrad
intruments and parts therof from the mid 90's

ALSO have B&G Hercules 390 spares, specifically 20/20 JUMBO displays
and interface box, and perhaps some analog wind, and digital MFD
displays...

... Can anyone please tell me how many pulses per nautical mile are delivered
by the B & G Sonic Speed system.

The B&G "Network" paddlewheel puts out a nominal 6.25Hz per Knot (at least
6.25 Hz is the factory-standard calibration setting). *That would work out
to 6.25 x 3600 = 22,500 pulses per nautical mile. *This is very likely the
same paddlewheel sensor that the Sonic unit is emulating.