AX2550 (2 ch) questions

I will be using the 2550 controller to operate a linear actuator and a motor/gear. The controller will be connected to an Arduino Mega. Feedback will be from 10k pots, and commands sent to the controller through rs-232. I've read the manual for the controller and it looks like it will be easy to send a position/speed command to the controller, e.g., "ch1, forward, to this position, at this speed", or just "Ch1, position, speed". I just wanted to verify that this is possible after the feedback endpoints are set. Also, are there any special considerations connecting the Arduino's TTL serial ports to the 2550? I am assuming here that I set the serial parameters on the Arduino to 9600 7E1 and run it through a 7404 inverter, yes?

The AX2550 will work, but you may consider the HDC2450. The later has a smoother and more precise position algorithm. It also includes scripting (i.e. like an on-board arduino) so that you can program it to do special motions.
As far as 5VTTL serial, it would need to go through an inverter. We believe it will work but we need to verify.