They're a separate device into which the toilet--ANY toilet, manual or electric--flushes and waste is treated. They're an alternative to a holding tank, not the alternative to a toilet. And except for the VacuFlush, all toilets designed to use pressurized flush water (fresh water) ARE macerating electric toilets.

The difference? Manual toilets are piston/cylinder pumps that pull in flush water and push waste and flush water out of the bowl and down the road to the tank, thru-hull...or treatment device. Electric macerating toilets are typically impeller pumps powered by a motor that also have a doodad in 'em that's essentially a blender blade called a "macerator." There are both sea water and pressurized versions of macerating electric toilets. The sea water versions have intake pumps...pressurized flush water versions do not have intake pumps, but have a solenoid valve instead.

Before someone gets all excited...Yes, there are a couple of other versions...the Lavac pump isn't a piston/cylinder pump...and not all electric toilets are macerating electric toilets. But most are what I described above,

So my guess...his toilets were macerting electric toilets designed by the toilet mfr to use pressurized flush water. And if they were on a Hunter, the odds are 100-1 that they were Jabsco 37010-series...one of these:

http://www.jabsco.com/products/marine-c1/toilet-waste-systems/electric-toilets/index.htm

And that concludes today's "marine toilets 101" lecture. Have a nice weekend all.