I have a Harris Pro 2000 toner and probe that my father left me but I do not have any instructions. I need to rewire a three way circuuit in the basement and need to know which three conductor cable goes to which switch. I believe I can use the use the tone tester to indentify which line goes to which switch but would prefer to read some direction before I hook anything to the circuit. Do you have a source for directions on using the circuit tester? My intension is to eliminate some of the lights from the three was switch.

I would determine which wire is hot, identify. The other switch location should have the lights switch leg. The hot goes to the common of 1 3 way, the switchleg goes to the other 3 way switchs common.
Then the travellers are left, Test for voltage on the conductors, then measure resistance to groun/neutral. Needs to have NO connection with either, measure continuity between the 2 wires thought to be travellers, if open, the hook toner to those 2 wires, go to other switch location, and check for tone, should be there.
Since there is no voltage from previous test, touch the 2 wires together with inductive amp near wire to see if it knocks out the tone, if it does, you are on same pair. Then hook to each switchs travellers location(brass screws/not the black common).
Toners are great for phone, alarm, TV, computer and other wiring.
An Example is a Junction box having all coaxes through the house and 1 from outside, connect tone to outside, go to numerous cables in house to determine the input, all others should be output.