It's all happy now thanks to Christos Zoulas and Christian Limpach.

The first thing I did was try out the sabtty support. I have an AceCat
III tablet and a Garmin GPS that I would like to drive from a 'real'
computer. Can anyone explain why the SAB based serial ports are now
ttyh0 and ttyh1 instead of ttya and ttyb? The lack of a manual page
didn't help me find the new names either. Mutter, grumble...

If nobody else has a manual page squirelled away somewhere, I'll whip
one up and submit it.

Lloyd