May I ask why? It would help to post information for specs and how you intend to use that controller. In many cases another controller ( with the exception of a transistor , relay , or h bridge) you wont need additional equipment.

The bioloid CM-5 controller can be operated by remote control via an IR receiver on one of it's sensor module (Dynamixel AX-S1 Sensor Module).

What I am trying to do is have the CM-5 controller, that uses a Atmega128 microcontroller, do all the motor processing for the robot and use the EZ-B to perform the high level functions, such has image processing and dicision/memory functions.

The idea is to see if the robot can teach itself something as simple as standing up and move around.

I am new to all this and its been something I've wanted to do since I was young.
I think it's great that you created a system for people like myself to experiment with.

ez_b doesn't work alone it uses your computer to do the high speed stuff

Actually the ezb doesn't process any data it is just a remote interface to connect to a host computer which does everything. I would just not bother with a second controller. Thats my opinion.