FALANT:
The FALANT is just a short way of saying "Farnsworth Lantern"... it is the same thing. The FALANT is a military color test that is basically a black box that has two lights on it which can be set to three different lights (green, red, white). The two lights are approximately once inch vertically-apart.
In this test, you need to identify the colors which are given to you from top to bottom; there are nine possible combinations (i.e. White, White; Red, Red; White, Green). You are given three sets of the nine combinations (27 total combinations). In order to pass, you must get 1 or less errors in at least 2/3 of these sets.
The good thing about this test is you can take it as much times as you want. Here is a picture of this test:
Light Signal Gun Test:
This test is administered on the airport taxiway/runway area in which you must identify the flashes of lights given to you from the control tower; these colors may be: Green, Red, White. You are given 5 seconds to identify each flash. They made me do this at two different locations (one at 1000 feet and the other at 1500 feet).
This test is generally much easier for color deficient people. However, you are only allowed to take this test once without the SODA.
If you fail the first time, then you will have the option to take this test at night for a SODA.
If you fail a second try, then they will send the results to the FAA Headquarters in Oklahoma City for further review.
I could not find a picture of the Light Signal Gun Test... but just imagine the intensity of a beacon (not rotating) flashing at you from the control tower.
-----
The decision is up to you:
You can try taking the FALANT first (at the FAA or otherwise). If you need to take it again, do so for a second or maybe third time. In the event you are unable to pass the FALANT after two or three times, then go for the Light Signal Gun Test (which I was able to pass without incident).
OR
You can go straight for the Light Signal Gun Test. The end result of this test is the same letter you get from passing the Farnsworth (assuming you pass the first time).
Any other questions?