Understanding Defensive Fire

[ComradeP]

For your units, during your turn:
1) Non-mortar and non-artillery units that have not moved during your turn can fire three times.
2) Mortar units and units that have moved during your turn can fire once or twice, depending on remaining movement points relative to their total movement points.
3) Artillery can fire once.

Also:
4) During your turn, all enemy units (on and off-map) can theoretically fire an unlimited number of times as opportunity fire, when your units take an action that can result in opportunity fire.
5) During the enemy turn, all your units (on and off-map) can theoretically fire an unlimited number of times as opportunity fire, when the enemy takes an action that can result in opportunity fire.

One difference is that, I believe, each action only draws opportunity fire from a specific enemy unit once in Panzer Battles, whereas in Panzer Campaigns a unit might expend all 3 of its opportunity fire attempts after a single action by a single unit.