Traveling again, (texting from 30,000 feet ), when I return in a week the dynamixels should be waiting for me. I'll give them the run through.

DJ, the dynamixel RS-485 servos have 4 pins.

They are gnd , vdd, d+, and d-. Would you connect EZ-B v4 pin D5 to the d+ pin and d- pin to gnd?

For the dynamixel TTL servos the connection is more straight forward.

D5 connects to the data pin on the 3 pin connector.

Incorrect, please read the following: http://support.robotis.com/en/product/dynamixel/dxl_mx_main.htm

Sparkfun.com has some nice breakout boards that can be used to go from RS485 to UART serial.

@DJ Sures, Thanks for finding the page on hooking up Dynamixel Servos. I had been reading it a while before I posted the warning about the Dynamixel RS485 servos and I guess I didn't explain it well. I have worked with RS485 before and didn't think the connection grounding the D- and sending data into the D+ pin would work but I never tried it so I thought I would check. The problem is that the RS485 bus is a differential bus. And I couldn't see how the EZ-B v4 could support it directly but didn't know for sure. You are the expert there.

@Robot-Doc. The Spark fun breakout ( https://www.sparkfun.com/products/10124 ) would be a great solution for just controlling the Dynamixel RS485 servos. If you want to both control and get data from the dynamixel servos you would need to control the direction pin on the breakout. It is setup so the Driver/Receiver Enable connected to normally connected to the RTS line. The EZ-B v4 documentation does not talk about RTS on the D5 uart used for the Dynamixel servos. So I don't see how a Dynamixel RS485 servo could be made to easily work on D5 uart if feedback is needed. I think the hope was that at some point the feedback data from the Dynamixel servos could be used by ARC and the EZ-SDK. With all the computing power they have put into the new EZ-B v4 it should be possible. I don't know as any of the feedback functions have been implemented yet or if they can be made to work. Thankfully for the project I have in mind I don't need feedback and Dynamixel has a TTL interface version of the servo I need. Just need an EZ-B v4 now and money of course. Dynamixel servos are not cheap. The 3D printed parts I am looking at are designed for the Dynamixel servos and it would be a lot of work to redesign for standard servos.

@DJ Sures, I still see some EZ-B v4 D18 references in the Manuals for Dynamixel servos and I found where you fixed at least one I think. It may be an issue with the on line manuals not being up to date with your edits.

Thank DJ