The no fire current is used to allow testing the wiring of a set of explosives without setting them off. The all fire current is used to set them all off at once (subject to fusing time delays and the like).
Worry not, I am going somewhere with this.
A while back, osewalrus posted "Feld's Laws", which specified (among other things) that if you are going to threaten to use a hand grenade, you'd better be prepared to follow through. This, of course, referred to big bad threats used in negotiation. If you're going to threaten to sue someone if they don't do X, you'd better be prepared to do so, or face loss of credibility. And I agree with all of this.
However, it was also stated that you should state at which point you will pull the pin, so everybody knows. This is the point I disagree with.
Find out just what the people will submit to and you have found out the exact amount of injustice and wrong which will be imposed upon them — Frederick Douglass, 1857
The problem with this is that people, knowing at which point you will draw the line, will simply hover near it, giving you the maximum amount of annoyance. My tactic is subtly different. I explain that I'll haul out the hand grenade when I'm sufficiently annoyed, but I don't nail down exactly when that will occur. I also point out that the point will vary unpredictably. I won't pull it out for trivial things (people who do are considered unstable and dangerous and are avoided — this is my no-fire point). And if things get completely out of hand, I'll always do it. And in the realm between these points, people had best watch themselves.
The result of this is that people are unwilling to test my mettle, lest I retaliate. This saves me a huge amount of energy and annoyance, and motivates people to be willing to negotiate and compromise. I do gain a reputation as an unpredictable hothead, but I'm willing to live with that.