How are AudioControl Active Balanced Technology products different from "Baluns"?
What Is a Balun?
The definition of a balun is a device which takes an unbalanced audio or video signal and converts it to a balanced signal (or vice versa).  Most common are passive baluns which are transformers.  Less common are active baluns which require an external power source.
What are the AudioControl Active Balanced Technology products?
The AudioControl Active Balanced Technology products are active baluns in that they take an unblanced signal and convert it to balanced (and vice versa).  Since they add other features such as cable compensation and gain makeup, AudioControl products are much more than what is usually meant by the term balun.
Active Balanced Technology products include:
Analog Audio  
BLD-10 BLR-10
Video & Audio  
BVD-10 BVR-10
Hi-Def Video & Digital Audio 
BVD-20 BVR-20
BVH-20 BVR-25
Maestro M2e