All HQ - HZ commercial would be linkage auto shift. Some Statesmans HZ & WB had a cable shift, I have heard, but never actually noticed for sure.

Have heard of cables seizing up, or snapping (probably through lack of maintenance) would depend how rough on your gear you are I suppose.

Linkage is simple, & you know what they say.... K.I.S.S.

Some aftermarket shifter kits came with cable, & from memory were cheaply made & dicky to use. I'm not an x spert, so this is just my opinion, see if someone can give you some more detail info

Cheers
Max